Hydroxyamidino derivatives useful as nitric oxide synthase inhibitors

ABSTRACT

The current invention discloses hydroxyamidino derivatives useful as nitric oxide synthase inhibitors.

This is a division of U.S. application Ser. No. 09/038,292, filed onMar. 11, 1998, now U.S. Pat. No. 6,207,708, which is acontinuation-in-part of U.S. application Ser. No. 08/813,545, filed onMar. 5, 1997, now U.S. Pat. No. 5,981,511, which is acontinuation-in-part of U.S. application Ser. No. 08/689,463, filed onAug. 8, 1996, now U.S. Pat. No. 5,945,408.

BACKGROUND OF THE INVENTION RELATED ART

It has been known since the early 1980's that the vascular relaxationcaused by acetylcholine is dependent on the presence of the vascularendothelium and this activity was ascribed to a labile humoral factortermed endothelium-derived relaxing factor (EDRF). The activity ofnitric oxide (NO) as a vasodilator has been known for well over 100years. In addition, NO is the active component of amylnitrite,glyceryltrinitrate and other nitrovasodilators. The recentidentification of EDRF as NO has coincided with the discovery of abiochemical pathway by which NO is synthesized from the amino acidL-arginine by the enzyme NO synthase.

Nitric oxide is the endogenous stimulator of the soluble guanylatecyclase. In addition to endothelium-dependent relaxation, NO is involvedin a number of biological actions including cytotoxicity of phagocyticcells and cell-to-cell communication in the central nervous system (seeMoncada et al., Biochemical Pharmacology, 38, 1709-1715, 1989; Moncadaet al., Pharmacological Reviews, 43, 109-142, 1991). Excess NOproduction appears to be involved in a number of pathologicalconditions, particularly conditions which involve systemic hypotensionsuch as toxic shock, septic shock and therapy with certain cytokines(Kerwin et al., J. Medicinal Chemistry, 38, 4343-4362, 1995).

The synthesis of NO from L-arginine can be inhibited by the L-arginineanalogue, L-N-monomethyl-arginine (L-NMMA) and the therapeutic use ofL-NMMA for the treatment of toxic shock and other types of systemichypotension has been proposed (WO 91/04024 and GB-A-2240041). Thetherapeutic use of certain other NO synthase inhibitors apart fromL-NMMA for the same purpose has also been proposed in WO 91/04024 and inEP-A-0446699.

It has recently become apparent that there are at least three types ofNO synthase as follows:

(i) a constitutive, Ca++/calmodulin dependent enzyme, located in theendothelium, that releases NO in response to receptor or physicalstimulation.

(ii) a constitutive, Ca++/calmodulin dependent enzyme, located in thebrain, that releases NO in response to receptor or physical stimulation.

(iii) a Ca++ independent enzyme which is induced after activation ofvascular smooth muscle,macrophages, endothelial cells, and a number ofother cells by endotoxin and cytokines. Once expressed this inducible NOsynthase generates NO continuously for long periods.

The NO released by the two constitutive enzymes acts as a transductionmechanism underlying several physiological responses. The NO produced bythe inducible enzyme is a cytotoxic molecule for tumor cells andinvading microorganisms. It also appears that the adverse effects ofexcess NO production, in particular pathological vasodilation and tissuedamage, may result largely from the effects of NO synthesized by theinducible NO synthase (Knowles and Moncada, Biochem J., 298, 249-258,1994 Billiar et al., Annals of Surgery, 221, 339-349, 1995; Davies etal., 1995)

There is also a growing body of evidence that NO may be involved in thedegeneration of cartilage which takes place in cerain conditions such asarthritis and it is also known that NO synthesis is increased inrheumatoid arthritis and in osteoarthritis (McInnes et al., J. Exp. Med,184, 1519-1524, 1996; Sakurai et al., J. Clin. Investig., 96, 2357-2363,1995). Accordingly, conditions in which there is an advantage ininhibiting NO production from L-arginine include autoimmune and/orinflammatory conditions affecting the joints, for example arthritis, andalso inflammatory bowel disease, cardivascular ischemia, diabetes,congestive heart failure, myocarditis, atherosclerosis, migraine, refluxesophagitis, diarrhea, irritable bowel syndrome, cystic fibrosis,emphysema, asthma, bronchiectasis, hyperalgesia (allodynia), cerebralischemia (both focal ischemia, thrombotic stroke and global ischemia(secondary to cardiac arrest), multiple sclerosis and other centralnervous system disorders mediated by NO, for example Parkinson's diseaseand Alzheimer's disease, and other disorders mediated by NO includingopiate tolerance in patients needing protracted opiate analgesics, andbenzodiazepine tolerance in patients taking benzodiazepines, and otheraddictive behaviour, for example, nicotine and eating disorders (Kerwinet al., J. Medicinal Chemistry, 38, 4343-4362, 1995; Knowles andMoncada, Biochem J., 298, 249-258, 1994; Davies et al., 1995;Pfeilschifter et al., Cell Biology International, 20, 51-58, 1996).

Further conditions in which there is an advantage in inhibiting NOproduction from L-arginine include systemic hypotension associated withseptic and/or toxic shock induced by a wide variety of agents; therapywith cytokines such as TNF, IL-1 and IL-2; and as an adjuvant to shortterm immunosuppression in transplant therapy (E. Kelly et al., J.Partent. Ent. Nutri., 19, 234-238, 1995; S. Moncada and E. Higgs, FASEBJ., 9, 1319-1330, 1995; R. G. Kilbourn et al, Crit. Care Med., 23,1018-1024, 1995).

Some of the NO synthase inhibitors proposed for therapeutic use so far,and in particular L-NMMA, are non-selective; they inhibit both theconstitutive and the inducible NO synthases. Use of such a non-selectiveNO synthase inhibitor requires that great care be taken in order toavoid the potentially serious consequences of over-inhibition of theconstitutive NO-synthase including hypertension and possible thrombosisand tissue damage. In particular, in the case of the therapeutic use ofL-NMMA for the treatment of toxic shock it has been recommended that thepatient must be subject to continuous blood pressure monitoringthroughout the treatment. Thus, while non-selective NO synthaseinhibitors have therapeutic utility provided that appropriateprecautions are taken, NO synthase inhibitors which are selective in thesense that they inhibit the inducible NO synthase to a considerablygreater extent than the constitutive isoforms of NO synthase would be ofeven greater therapeutic benefit and easier to use (S. Moncada and E.Higgs, FASEB J., 9, 1319-1330, 1995).

WO 96/35677, WO 96/33175, WO 96/15120, WO 95/11014, WO 95/11231 WO95/25717, WO 95/24382, WO94/12165, WO94/14780, WO93/13055, EP0446699A1and U.S. Pat. No. 5,132,453 disclose compounds that inhibit nitric oxidesynthesis and preferentially inhibit the inducible isoform of nitricoxide synthase. The disclosures of which are hereby incorporated byreference in their entirety as if written herein.

SUMMARY OF THE INVENTION

In a broad aspect, the present invention is directed to inhibiting ormodulating nitric oxide synthesis in a subject in need of suchinhibition or modulation by administering a compound whichpreferentially inhibits or modulates the inducible isoform of nitricoxide synthase over the constitutive isoforms of nitric oxide synthase.It is also another object of the present invention to lower nitric oxidelevels in a subject in need of such lowering.

Compounds of the present invention are represented by the followingchemical formula:

and pharmaceutically acceptable salts, wherein:

A is selected from O (oxygen) or S and may be taken together with R⁴ toform a heterocyclic ring; or

A is N when R³ and R⁷ are taken together to form a heterocyclic ring; orR⁵ and A—R³ are taken together to form a covalent bond; or

A is N—R³ provided R³ is not a heterocyclic radical; or

A is a heterocyclic ring;

R¹ is not present or is selected from the group consisting of hydrogen,hydroxyalkyl, alkoxyalkyl, alkyl and haloalkyl;

R² is selected from the group consisting of straight and branched alkyl,alkenyl, and alkynyl, cycloalkyl, cycloalkenyl, haloalkyl; alloptionally substituted by one or more of hydrogen, alkyl, alkoxy,hydroxy, halogen, trifluoromethyl, nitro, cyano, or amino groups;

R³ is selected from the group consisting of aryl, heteroaryl, alkylaryl,alkylheteroaryl, all optionally substituted by one or more of halogen,nitrile, carboxy, carboxyalkyl, carboxyalkylaryl; or

R³ is selected from the group consisting of H, alkyl, alkenyl,CH₂OC(═O)YR⁶, alkylhydroxy, alkylpolyhydroxy, amino, hydroxy,alkyl(poly)oxyacyl, alkylcarboxy, optionally substituted by one or moreof alkyl, hydroxy, amino, carboxy, carboxyalkyl, alkylcarbonyl;

R⁴ is selected from H, OH, SH, OR⁶, SR⁶, OC(═O)R⁶, SC(═O)R⁶,CH₂OC(═O)YR⁶, OC(═O)YR⁶, SC(═O)YR⁶, OSO₂R⁶, OS(O)R⁶;

Y is independently selected from O, S, CH₂, CHR⁶, C(R⁶)₂, NH, NR⁶;

R⁵ is selected from H, OH, SH, OR⁶, SR⁶, OC(═O)R⁶, SC(═O)R⁶,CH₂OC(═O)YR⁶, OC(═O)YR⁶, SC(═O)YR⁶, OSO₂R⁶, OS(O)R⁶;

R⁶ is selected from hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl,heterocyclic, aryl, heteroaryl all optionally substituted by one or morealkyl, alkoxy, hydroxy, halogen, trifluoromethyl, nitro, cyano, or aminogroups;

R⁷ is selected from H, S(O)R⁹, SO₂R⁹, CH₂OC(O)—R⁹, C(O)—R⁹ where C(O)—R⁹can represent natural and synthetic amino acids or R⁹ can be defined asbelow, or R⁷ and R³ taken together comprise a 5- or 6- memberedheterocyclic ring containing two or more heteroatoms, optionallysubstituted with alkyl and/or oxygen functions including carbonyl, ortaken together comprise a metal complex containing a divalent cation, ora boron complex;

R⁸ is selected from H, acyl;

provided that R⁴, R⁵, R⁷ and R⁸ are not simultaneously hydrogen, exceptwhen Q is SiE₂;

R⁹ is selected from substituted dihydropyridyl, alkyl, thioalkoxy,alkoxy, amino, cycloalkoxy, optionally substituted with one or more ofamino, alkyl, alkylaryl, heteroaryl, alkylheteroaryl,alkylmercaptoalkyl, which may optionally be substituted with one or moreof hydroxy, amino, guanidino, iminoalkyl;

X is selected from the group consisting of alkylene, alkenylene andalkynylene and which may optionally be substituted by one or more alkyl,alkoxy, hydroxy, halogen, trifluoromethyl, nitro, cyano, or aminogroups; or

X is selected from the group consisting of the formula—(CH₂)_(k)Q(CH₂)_(t)— where k is 1, 2 or 3, t is 1, 2 or 3 and Q is O(oxygen), Se, SiE₂ where E is alkyl, aryl, S(O)_(g) where g is 0, 1 or2, or NR where R is H or alkyl which may be optionally substituted withalkyl, alkoxy, hydroxy, halogen, trifluoromethyl, nitro, cyano, amino;or

X is selected from the group consisting of the formula—(CH₂)_(m)T(CH₂)_(n)— where m is 0, 1 or 2, n is 0, 1 or 2, T is a 3 to6 membered carbocyclic or heterocyclic ring, aromatic ring orheteroaromatic ring which may optionally be substituted by one or moresubstituents selected from the group consisting of alkyl, alkoxy,hydroxy, halogen, nitro, cyano, trifluoroalkyl and amino.

It is an object of the present invention to provide compounds that haveusefulness as inhibitors of nitric oxide synthase. These compounds alsopreferentially inhibit the inducible form over the constitutive forms.

DETAILED DESCRIPTION OF THE INVENTION

and pharmaceutically acceptable salts, wherein:

A is selected from O (oxygen) or S and may be taken together with R⁴ toform a heterocyclic ring; or

A is N when R³ and R⁷ are taken together to form a heterocyclic ring; orR⁵ and A—R³ are taken together to form a covalent bond; or

A is N—R³ provided R³ is not a heterocyclic radical; or

A is a heterocyclic ring;

R¹ is not present or is selected from the group consisting of hydrogen,hydroxyalkyl, alkoxyalkyl, alkyl and haloalkyl;

R² is selected from the group consisting of straight and branched alkyl,alkenyl, and alkynyl, cycloalkyl, cycloalkenyl, haloalkyl; alloptionally substituted by one or more of hydrogen, alkyl, alkoxy,hydroxy, halogen, trifluoromethyl, nitro, cyano, or amino groups;

R³ is selected from the group consisting of aryl, heteroaryl, alkylaryl,alkylheteroaryl, all optionally substituted by one or more of halogen,nitrile, carboxy, carboxyalkyl, carboxyalkylaryl; or

R³ is selected from the group consisting of H, alkyl, alkenyl,CH₂OC(═O)YR⁶, alkylhydroxy, alkylpolyhydroxy, amino, hydroxy,alkyl(poly)oxyacyl, alkylcarboxy, optionally substituted by one or moreof alkyl, hydroxy, amino, carboxy, carboxyalkyl, alkylcarbonyl;

R⁴ is selected from H, OH, SH, OR⁶, SR⁶, OC(═O)R⁶, SC(═O)R⁶,CH₂OC(═O)YR⁶, OC(═O)YR⁶, SC(═O)YR⁶, OSO₂R⁶, OS(O)R⁶;

Y is independently selected from O, S, CH₂, CHR⁶, C(R⁶)₂, NH, NR⁶;

R⁵ is selected from H, OH, SH, OR⁶, SR⁶, OC(═O)R⁶, SC(═O)R⁶,CH₂OC(═O)YR⁶, OC(═O)YR⁶, SC(═O)YR⁶, OSO₂R⁶, OS(O)R⁶;

R⁶ is selected from hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl,heterocyclic, aryl, heteroaryl all optionally substituted by one or morealkyl, alkoxy, hydroxy, halogen, trifluoromethyl, nitro, cyano, or aminogroups;

R⁷ is selected from H, S(O)R⁹, SO₂R⁹, CH₂OC(O)—R⁹, C(O)—R⁹ where C(O)—R⁹can represent natural and synthetic amino acids or R⁹ can be defined asbelow, or R⁷ and R³ taken together comprise a 5- or 6- memberedheterocyclic ring containing two or more heteroatoms, optionallysubstituted with alkyl and/or oxygen functions including carbonyl, ortaken together comprise a metal complex containing a divalent cation, ora boron complex;

R⁸ is selected from H, acyl;

provided that R⁴, R⁵, R⁷ and R⁸ are not simultaneously hydrogen, exceptwhen Q is SiE₂;

R⁹ is selected from substituted dihydropyridyl, alkyl, thioalkoxy,alkoxy, amino, cycloalkoxy, optionally substituted with one or more ofamino, alkyl, alkylaryl, heteroaryl, alkylheteroaryl,alkylmercaptoalkyl, which may optionally be substituted with one or moreof hydroxy, amino, guanidino, iminoalkyl;

X is selected from the group consisting of alkylene, alkenylene andalkynylene and which may optionally be substituted by one or more alkyl,alkoxy, hydroxy, halogen, trifluoromethyl, nitro, cyano, or aminogroups; or

X is selected from the group consisting of the formula—(CH₂)_(k)Q(CH₂)_(t)— where k is 1, 2 or 3, t is 1, 2 or 3 and Q is O(oxygen), Se, SiE₂ where E is alkyl, aryl, S(O)_(g) where g is 0, 1 or2, or NR where R is H or alkyl which may be optionally substituted withalkyl, alkoxy, hydroxy, halogen, trifluoromethyl, nitro, cyano, amino;or

X is selected from the group consisting of the formula—(CH₂)_(m)T(CH₂)_(n)— where m is 0, 1 or 2, n is 0, 1 or 2, T is a 3 to6 membered carbocyclic or heterocyclic ring, aromatic ring orheteroaromatic ring which may optionally be substituted by one or moresubstituents selected from the group consisting of alkyl, alkoxy,hydroxy, halogen, nitro, cyano, trifluoroalkyl and amino.

A preferred embodiment of the present invention is a compound of theformula (I):

and pharmaceutically acceptable salts, wherein:

A is selected from O (oxygen) or S and may be taken together with R⁴ toform a heterocyclic ring; or

A is N when R³ and R⁷ are taken together to form a heterocyclic ring; orR⁵ and A—R³ are taken together to form a covalent bond; or

A is N—R³ provided R³ is not a heterocyclic radical; or

A is a heterocyclic ring;

R¹ is selected from the group consisting of hydrogen, hydroxyalkyl offrom 1 to 4 carbon atoms, alkoxyalkyl of from 1 to 4 carbon atoms ineach position, alkyl of from 1 to 8 carbon atoms and haloalkyl of from 1to 4 carbon atoms;

R² is selected from the group consisting of straight and branched alkylof from 1 to 4 carbon atoms, alkenyl and alkynyl of from 2 to 4 carbonatoms, cycloalkyl of from 1 to 4 carbon atoms, cycloalkenyl of from 3 to8 carbon atoms, and haloalkyl of from 1 to 4 carbon atoms; alloptionally substituted by one or more of hydrogen, alkyl, alkoxy,hydroxy, halogen, trifluoromethyl, nitro, cyano, or amino groups;

R³ is selected from the group consisting of aryl, heteroaryl, alkylaryl,alkylheteroaryl, all optionally substituted by one or more of halogen,nitrile, carboxy, carboxyalkyl, carboxyalkylaryl; or

R³ is also selected from the group consisting of H, alkyl of from 1 to 4carbon atoms, alkenyl of from 2 to 4 carbon atoms, CH₂OC(═O)YR⁶,alkylhydroxy, alkylpolyhydroxy, alkyl(poly)oxyacyl, alkylcarboxy, amino,hydroxy, optionally substituted by one or more of alkyl of from 1 to 4carbon atoms, hydroxy, amino, carboxy, carboxyalkyl, alkylcarbonyl;

R⁴ is selected from H, OH, SH, OR⁶, SR⁶, OC(═O)R⁶, SC(═O)R⁶,CH₂OC(═O)YR⁶, OC(═O)YR⁶, SC(═O)YR⁶;

Y is independently selected from O, S, CH₂, CHR⁶, C(R⁶)₂, NH, NR⁶;

R⁵ is selected from H, OH, SH, OR⁶, SR⁶, OC(═O)R⁶, SC(═O)R⁶,CH₂OC(═O)YR⁶, OC(═O)YR⁶, SC(═O)YR⁶;

R⁶ is selected from hydrogen, alkyl of from 1 to 4 carbon atoms, alkenyland alkynyl of from 2 to 4 carbon atoms, cycloalkyl of from 3 to 8carbon atoms, heterocyclic of from 5 to 8 members, aryl,.heteroaryl alloptionally substituted by one or more alkyl of from 1 to 4 carbon atoms,alkoxy, hydroxy, halogen, trifluoromethyl, nitro, cyano, or aminogroups;

R⁷ is selected from H, S(O)R⁹, SO₂R⁹, CH₂OC(O)—R⁹, C(O)—R⁹ where C(O)—R⁹can represent natural and synthetic amino acids or R⁹ can be defined asbelow, or R⁷ and R³ taken together comprise a 5- or 6- memberedheterocyclic ring containing two or more heteroatoms, optionallysubstituted with alkyl of from 1 to 4 carbon atoms and/or oxygenfunctions including carbonyl, or taken together comprise a metal complexcontaining a divalent cation, or a boron complex;

R⁸ is selected from H, acyl;

provided that R⁴, R⁵, R⁷ and R⁸ are not simultaneously hydrogen, exceptwhen Q is SiE₂;

R⁹ is selected from substituted dihydropyridyl, alkyl of from 1 to 4carbon atoms, thioalkoxy, alkoxy, amino, cycloalkoxy, optionallysubstituted with one or more of amino, alkyl of from 2 to 4 carbonatoms, alkylaryl, heteroaryl, alkylheteroaryl, alkylmercaptoalkyl, whichmay optionally be substituted with one or more of hydroxy, amino,guanidino, iminoalkyl;

X is selected from the group consisting of alkylene, alkenylene andalkynylene having 2 to 6 carbon atoms and which may optionally besubstituted by one or more alkyl groups; or

X is selected from the group consisting of the formula—(CH₂)_(k)Q(CH₂)_(t)— where k is 1, 2 or 3, t is 1, 2 or 3 and Q is O(oxygen), Se, SiE₂ where E is alkyl, aryl, S(O)_(g) where g is 0, 1 or2, or NR where R is H or alkyl which may be optionally substituted withalkyl, alkoxy, hydroxy, halogen, trifluoromethyl, nitro, cyano, amino;or

X is selected from the group consisting of the formula—(CH₂)_(m)T(CH₂)_(n)— where m is 0, 1 or 2, n is 0, 1 or 2, T is a 3 to6 membered carbocyclic or heterocyclic ring, aromatic ring orheteroaromatic ring which may optionally be substituted by one or moresubstituents selected from the group consisting of alkyl, alkoxy,hydroxy, halogen, nitro, cyano, trifluoroalkyl and amino.

A preferred embodiment of the present invention is a compound of theformula (I):

and pharmaceutically acceptable salts, wherein:

A is selected from O (oxygen) or S and may be taken together with R⁴ toform a heterocyclic ring; or

A is N when R³ and R⁷ are taken together to form a heterocyclic ring; orR⁵ and A—R³ are taken together to form a covalent bond; or

A is N—R³ provided R³ is not a heterocyclic radical; or

A is a heterocyclic ring;

R¹ is selected from the group consisting of hydrogen, hydroxyalkyl offrom 1 to 4 carbon atoms, alkoxyalkyl of from 1 to 4 carbon atoms ineach position, alkyl of from 1 to 8 carbon atoms and haloalkyl of from 1to 4 carbon atoms;

R² is selected from the group consisting of straight and branched alkylof from 1 to 4 carbon atoms, alkenyl and alkynyl of from 2 to 4 carbonatoms, cycloalkyl of from 1 to 4 carbon atoms, cycloalkenyl of from 3 to8 carbon atoms, and haloalkyl of from 1 to 4 carbon atoms; alloptionally substituted by one or more of hydrogen, alkyl, alkoxy,hydroxy, halogen, nitro, cyano, or amino groups;

R³ is selected from the group consisting of aryl, heteroaryl, alkylaryl,alkylheteroaryl, all optionally substituted by one or more of halogen,nitrile, carboxy, carboxyalkyl, carboxyalkylaryl; or

R³ is also selected from the group consisting of H, alkyl of from 1 to 4carbon atoms, alkenyl of from 2 to 4 carbon atoms, CH₂OC(═O)YR⁶,alkylhydroxy, alkylpolyhydroxy, alkyl(poly)oxyacyl, alkylcarboxy, amino,hydroxy;

R⁴ is selected from H, OH, SH, OR⁶, SR⁶, OC(═O)R⁶, SC(═O)R⁶,CH₂OC(═O)YR⁶;

Y is independently selected from O, S, CH₂, CHR⁶, C(R⁶)₂, NH, NR⁶;

R⁵ is selected from H, OH, SH, OR⁶, SR⁶, OC(═O)R⁶, SC(═O)R⁶,CH₂OC(═O)YR⁶;

R⁶ is selected from hydrogen, alkyl of from 1 to 4 carbon atoms, alkenyland alkynyl of from 2 to 4 carbon atoms, cycloalkyl of from 3 to 8carbon atoms, heterocyclic of from 5 to 8 members, aryl, heteroaryl alloptionally substituted by one or more alkyl of from 1 to 4 carbon atomsor hydroxy groups;

R⁷ is selected from H, S(O)R⁹, SO₂R⁹, CH₂OC(O)—R⁹, C(O)—R⁹ where C(O)—R⁹can represent natural and synthetic amino acids or R⁹ can be defined asbelow, or R⁷ and R³ taken together comprise a 5- or 6- memberedheterocyclic ring containing two or more heteroatoms;

R⁸ is selected from H, acyl;

provided that R⁴, R⁵, R⁷ and R⁸ are not simultaneously hydrogen, exceptwhen Q is SiE₂;

R⁹ is selected from substituted dihydropyridyl, alkyl of from 1 to 4carbon atoms, thioalkoxy, alkoxy, amino, cycloalkoxy;

X is selected from the group consisting of alkylene, alkenylene andalkynylene having 2 to 6 carbon atoms and which may optionally besubstituted by one or more alkyl groups; or

X is selected from the group consisting of the formula—(CH₂)_(k)Q(CH₂)_(t)— where k is 2 or 3, t is 1 or 2 and Q is O(oxygen), Se, SiE₂ where E is alkyl, aryl, S(O)g where g is 0, 1 or 2,or NR where R is H or alkyl which may be optionally substituted withalkyl; or

X is selected from the group consisting of the formula—(CH₂)_(m)T(CH₂)_(n)— where m is 0, 1 or 2, n is 0, 1 or 2, T is a 3 to6 membered carbocyclic or heterocyclic ring, aromatic ring orheteroaromatic ring which may optionally be substituted by one or moresubstituents selected from the group consisting of alkyl, alkoxy,hydroxy, halogen, nitro, cyano, trifluoroalkyl and amino.

Another preferred embodiment of the present invention is a compound ofthe formula (I) and pharmaceutically acceptable salts; wherein:

A is selected from O (oxygen) and may be taken together with R⁴ to forma heterocyclic ring; or

A when R⁵ and A—R³ are taken together forms a covalent bond;

A is N—R³ where the R³ radicals are selected from hydrogen, alkyl offrom 1 to 4 carbon atoms or aryl; or

A is a heterocyclic ring containing from 1 to 4 nitrogen atoms;

R¹ is selected from the group consisting of hydrogen, hydroxyalkyl offrom 1 to 4 carbon atoms and alkyl of from 1 to 8 carbon atoms;

R² is selected from the group consisting of straight and branched alkylof from 1 to 4 carbon atoms and haloalkyl of from 1 to 4 carbon atoms;all optionally substituted by one or more of hydrogen, alkyl, alkoxy,hydroxy, halogen, or amino groups;

R³ is selected from the group consisting of aryl, heteroaryl, alkylaryl,alkylheteroaryl, all optionally substituted by one or more of halogen,nitrile, carboxy, carboxyalkyl, carboxyalkylaryl; or

R³ is also selected from the group consisting of H, amino, hydroxy,alkyl of from 1 to 4 carbon atoms and alkenyl of from 2 to 4 carbonatoms;

R⁴ is selected from H, OH, SH, OR⁶, SR⁶; R⁵ is selected from H, OH, SH,OR⁶, SR⁶;

R⁶ is selected from hydrogen, alkyl of from 1 to 4 carbon atoms, alkenyland alkynyl of from 2 to 4 carbon atoms and cycloalkyl of from 3 to 8carbon atoms;

R⁷ is selected from H and where C(O)—R⁹ can represent natural andsynthetic amino acids;

provided that R⁴, R⁵, R⁷ and R⁸ are not simultaneously hydrogen, exceptwhen Q is SiE₂;

R⁸ is selected from H and acyl;

X is selected from the group consisting of alkylene, alkenylene andalkynylene having 2 to 6 carbon atoms and which may optionally besubstituted by one or more alkyl groups; or

X is selected from the group consisting of the formula—(CH₂)_(k)Q(CH₂)_(t)— where k is 2 or 3, t is 1 or 2 and Q is O(oxygen), S(O)_(g) where g is 0, 1 or 2, or NR where R is H or alkyl or

X is selected from the group consisting of the formula—(CH₂)_(m)T(CH₂)_(n)— where m is 0, 1 or 2, n is 0, 1 or 2, T is a 3 to6 membered carbocyclic or heterocyclic ring, aromatic ring orheteroaromatic ring.

Another preferred embodiment of the present invention is a compound ofthe formula (I) and pharmaceutically acceptable salts; wherein:

A is O (oxygen); or

A is a heterocyclic ring containing from 1 to 4 nitrogen atoms;

R¹ is selected from the group consisting of hydrogen, hydroxyalkyl offrom 1 to 4 carbon atoms and alkyl of from 1 to 8 carbon atoms;

R² is selected from the group consisting of straight and branched alkylof from 1 to 4 carbon atoms and haloalkyl of from 1 to 4 carbon atoms;all optionally substituted by one or more of hydrogen, alkyl, alkoxy,hydroxy, halogen, or amino groups;

R³ is selected from the group consisting of heteroaryl, alkylaryl,alkylheteroaryl, all optionally substituted by one or more of halogen,carboxy, carboxyalkyl; or

R³ is also selected from the group consisting of H or alkyl of from 1 to4 carbon atoms, amino;

R⁴ is selected from H, OH, SH, OR⁶, SR⁶;

R⁵ is selected from H, OH, SH, OR⁶, SR⁶;

R⁶ is selected from hydrogen, alkyl of from 1 to 4 carbon atoms andcycloalkyl of from 3 to 8 carbon atoms;

R⁷ is selected from H and where C(O)—R⁹ can represent natural andsynthetic amino acids;

R⁸ is H; provided that R⁴, R⁵, R⁷ and R⁸ are not simultaneouslyhydrogen, except when Q is SiE₂;

X is selected from the group consisting of alkylene, alkenylene andalkynylene having 2 to 6 carbon atoms and which may optionally besubstituted by one or more alkyl groups; or

X is selected from the group consisting of the formula—(CH₂)_(k)Q(CH₂)_(t)— where k is 2 or 3, t is 1 or 2 and Q is O(oxygen), S(O)_(g) where g is 0, 1 or 2.

Another preferred embodiment of the present invention is a compound ofthe formula (I) and pharmaceutically acceptable salts; wherein:

A is O (oxygen);

R¹ is hydrogen;

R² is methyl;

R³ is selected from the group consisting of hydrogen, and alkyl of 1 toabout 4 carbon atoms;

R⁴ is hydroxy;

R⁵ is hydrogen or hydroxy;

R⁷ is hydrogen;

R⁸ is hydrogen;

X is an alkylene having 3 to 5 carbon atoms.

The present invention includes compounds of formula (I) in the form ofsalts, in particular acid addition salts. Suitable salts include thoseformed with both organic and inorganic acids. Such acid addition saltswill normally be pharmaceutically acceptable although salts ofnon-pharmaceutically acceptable salts may be of utility in thepreparation and purification of the compound in question. Thus,preferred salts include those formed from hydrochloric, hydrobromic,sulphuric, citric, tartaric, phosphoric, lactic, pyruvic, acetic,succinic, fumaric, maleic, oxaloacetic, methanesulphonic,ethanesulphonic, ρ-toluenesulphonic, benzenesulphonic and isethionicacids. Salts of the compounds of formula (I) can be made by reacting theappropriate compound in the form of the free base with the appropriateacid.

While it may be possible for the compounds of formula (I) to beadministered as the raw chemical, it is preferable to present them as apharmaceutical composition. According to a further aspect, the presentinvention provides a pharmaceutical composition comprising a compound offormula (I) or a pharmaceutically acceptable salt or solvate thereof,together with one or more pharmaceutically acceptable carriers thereofand optionally one or more other therapeutic ingredients. The carrier(s)must be “acceptable” in the sense of being compatible with the otheringredients of the formulation and not deleterious to the recipientthereof.

The formulations include those suitable for oral, parenteral (includingsubcutaneous, intradermal, intramuscular, intravenous andintraarticular), rectal and topical (including dermal, buccal,sublingual and intraocular) administration although the most suitableroute may depend upon for example the condition and disorder of therecipient. The formulations may conveniently be presented in unit dosageform and may be prepared by any of the methods well known in the art ofpharmacy. All methods include the step of bringing into association acompound of formula (I) or a pharmaceutically acceptable salt or solvatethereof (“active ingredient”) with the carrier which constitutes one ormore accessory ingredients. In general, the formulations are prepared byuniformly and intimately bringing into association the active ingredientwith liquid carriers or finely divided solid carriers or both and then,if necessary, shaping the product into the desired formulation.

Formulations of the present invention suitable for oral administrationmay be presented as discrete units such as capsules, cachets or tabletseach containing a predetermined amount of the active ingredient; as apowder or granules; as a solution or a suspension in an aqueous liquidor a non-aqueous liquid; or as an oil-in-water liquid emulsion or awater-in-oil liquid emulsion. The active ingredient may also bepresented as a bolus, electuary or paste.

A tablet may be made by compression or moulding, optionally with one ormore accessory ingredients. Compressed tablets may be prepared bycompressing in a suitable machine the active ingredient in afree-flowing form such as a powder or granules, optionally mixed with abinder, lubricant, inert diluent, lubricating, surface active ordispersing agent. Moulded tablets may be made by moulding in a suitablemachine a mixture of the powdered compound moistened with an inertliquid diluent. The tablets may optionally be coated or scored and maybe formulated so as to provide slow or controlled release of the activeingredient therein.

Formulations for parenteral administration include aqueous andnon-aqueous sterile injection solutions which may contain anti-oxidants,buffers, bacteriostats and solutes which render the formulation isotonicwith the blood of the intended recipient; and aqueous and non-aqueoussterile suspensions which may include suspending agents and thickeningagents. The formulations may be presented in unit-dose or multi-dosecontainers, for example sealed ampoules and vials, and may be stored ina freeze-dried (lyophilized) condition requiring only the addition ofthe sterile liquid carrier, for example, saline, water-for-injection,immediately prior to use. Extemporaneous injection solutions andsuspensions may be prepared from sterile powders, granules and tabletsof the kind previously described.

Formulations for rectal administration may be presented as a suppositorywith the usual carriers such as cocoa butter or polyethylene glycol.

Formulations for topical administration in the mouth, for examplebuccally or sublingually, include lozenges comprising the activeingredient in a flavoured basis such as sucrose and acacia ortragacanth, and pastilles comprising the active ingredient in a basissuch as gelatin and glycerin or sucrose and acacia.

Preferred unit dosage formulations are those containing an effectivedose, as herein below recited, or an appropriate fraction thereof, ofthe active ingredient.

It should be understood that in addition to the ingredients particularlymentioned above, the formulations of this invention may include otheragents conventional in the art having regard to the type of formulationin question, for example those suitable for oral administration mayinclude flavouring agents.

The compounds of the invention may be administered orally or viainjection at a dose of from 0.001 to 2500 mg/kg per day. The dose rangefor adult humans is generally from 0.005 mg to 10 g/day. Tablets orother forms of presentation provided in discrete units may convenientlycontain an amount of compound of the invention which is effective atsuch dosage or as a multiple of the same, for instance, units containing5 mg to 500 mg, usually around 10 mg to 200 mg.

The compounds of formula (I) are preferably administered orally or byinjection (intravenous or subcutaneous). The precise amount of compoundadministered to a patient will be the responsibility of the attendantphysician. However, the dose employed will depend on a number offactors, including the age and sex of the patient, the precise disorderbeing treated, and its severity. Also, the route of administration mayvary depending on the condition and its severity.

As utilized herein, the term “alkyl”, alone or in combination, means anacyclic alkyl radical containing from 1 to about 10, preferably from 1to about 8 carbon atoms and more preferably 1 to about 6 carbon atoms.Examples of such radicals include methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, iso-amyl, hexyl, octyland the like.

The term “alkenyl” refers to an unsaturated acyclic hydrocarbon radicalin so much as it contains at least one double bond. Such radicalscontaining from about 2 to about 10 carbon atoms, preferably from about2 to about 8 carbon atoms and more preferably 2 to about 6 carbon atoms.Examples of suitable alkenyl radicals include propylenyl, buten-1-yl,isobutenyl, pentenylen-1-yl, 2-2-methylbuten-1-yl, 3-methylbuten-1-yl,hexen-1-yl, hepten-1-yl, and octen-1-yl, and the like.

The term “alkynyl” refers to an unsaturated acyclic hydrocarbon radicalin so much as it contains one or more triple bonds, such radicalscontaining about 2 to about 10 carbon atoms, preferably having fromabout 2 to about 8 carbon atoms and more preferably having 2 to about 6carbon atoms. Examples of suitable alkynyl radicals include ethynyl,propynyl, butyn-1-yl, butyn-2-yl, pentyn-1-yl, pentyn-2-yl,3-methylbutyn-1-yl, hexyn-1-yl, hexyn-2-yl, hexyn-3-yl,3,3-dimethylbutyn-1-yl radicals and the like.

The term “heterocyclic radical” means an unsaturated cyclic hydrocarbonradical with 3 to about 6 carbon atoms, wherein 1 to about 4 carbonatoms are replaced by nitrogen, oxygen or sulfur. The “heterocyclicradical” may be fused to an aromatic hydrocarbon radical. Suitableexamples include pyrrolyl, pyridinyl, pyrazolyl, triazolyl, pyrimidinyl,pyridazinyl, oxazolyl, thiazolyl, imidazolyl, indolyl, thiophenyl,furanyl, tetrazolyl, 2-pyrrolinyl, 3-pyrrolinyl, pyrrolindinyl,1,3-dioxolanyl, 2-imidazolinyl, imidazolidinyl, 2-pyrazolinyl,pyrazolidinyl, isoxazolyl, isothiazolyl, 1,2,3-oxadiazolyl,1,2,3-triazolyl, 1,3,4-thiadiazolyl, 2H-pyranyl, 4H-pyranyl,piperidinyl, 1,4-dioxanyl, morpholinyl, 1,4-dithianyl, thiomorpholinyl,pyrazinyl, piperazinyl, 1,3,5-triazinyl, 1,3,5-trithianyl,benzo(b)thiophenyl, benzimidazonyl, quinolinyl, and the like.

The term “aryl” means an aromatic hydrocarbon radical of 6 to about 14carbon atoms, preferably 6 to about 10 carbon atoms. Examples ofsuitable aromatic hydrocarbon radicals include phenyl, naphthyl, and thelike.

The terms “cycloalkyl” or “cycloalkenyl” means an “alicyclic radical ina ring with 3 to about 10 carbon atoms, and preferably from 3 to about 6carbon atoms. Examples of suitable alicyclic radicals includecyclopropyl, cyclopropylenyl, cyclobutyl, cyclopentyl, cyclohexyl,2-cyclohexen-1-ylenyl, cyclohexenyl and the like.

The term “alkoxy”, alone or in combination, means an alkyl ether radicalwherein the term alkyl is as defined above and most preferablycontaining 1 to about 4 carbon atoms. Examples of suitable alkyl etherradicals include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy,iso-butoxy, sec-butoxy, tert-butoxy and the like.

The terms “alkylene”, “alkenylene” and “alkynylene” refers tohydrocarbons containing 2 to 10 carbon atoms, preferably 2 to 8 carbonatoms, and more preferably 2 to 6 carbon atoms.

The term “acyl” means alkyl or aryl carbonyl radicals. Examples includeacetyl, benzoyl, and the like.

The term “halogen” means fluorine, chlorine, bromine or iodine.

The term “prodrug” refers to a compound that is made more active invivo.

As used herein, reference to “treatment” of a patient is intended toinclude prophylaxis.

All references, patents or applications, U.S. or foreign, cited in theapplication are hereby incorporated by reference as if written herein.

The following general synthetic sequences are useful in making thepresent invention. Abbreviations used in the schemes are as follows:“Boc” represents tert-butyloxycarbonyl, “Z” or “bcz” representsbenzyloxycarbonyl “Fmoc” represents 9-fluorenylmethoxycarbonyl, “DIPEA”represents diisopropylethylamine, “DMF” represents dimethylformamide,and “TBTU” represents 2-(1H-benzotriozole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate.

Compounds of the present invention can exist in tautomeric, geometric orstereoisomeric forms. The present invention contemplates all suchcompounds, including cis- and trans-geometric isomers, E- andZ-geometric isomers, R- and S-enantiomers, diastereomers, d-isomers,l-isomers, the racemic mixtures thereof and other mixtures thereof, asfalling within the scope of the invention.

Disclosed are twenty-seven general synthetic processes useful in thepreparation of the compounds of the present invention.

Without further elaboration, it is believed that one skilled in the artcan, using the preceding descriptions, utilize the present invention toits fullest extent. Therefore the following preferred specificembodiments are to be construed as merely illustrative and notlimitative of the remainder of the disclosure in any way whatsoever.Compounds containing multiple variations of the structural modificationsillustrated in the preceding schemes or the following Examples are alsocontemplated.

All experiments were performed under either dry nitrogen or argon. Allsolvents and reagents were used without further purification unlessotherwise noted. The routine work-up of the reactions involved theaddition of the reaction mixture to a mixture of either neutral, oracidic, or basic aqueous solutions and organic solvent. The aqueouslayer was extracted n times (x) with the indicated organic solvent. Thecombined organic extracts were washed n times (x) with the indicatedaqueous solutions, dried over anhydrous Na₂SO₄, filtered, concentratedin vacuo, and purified as indicated. Separations by columnchromatography were achieved with conditions described by Still. (Still,W. C.; Kahn, M.; Mitra, A. Rapid Chromatograhic Technique forPreparative Separation with Moderate Resolution. J. Org. Chem., 1978,43, 2923-2925.) The hydrochloride salts were made from 1N HCl, HCl inethanol (EtOH), 2 N in MeOH, or 6 N HCl in dioxane. Thin layerchromatograms were run on 0.25 mm EM precoated plates of silica gel 60F254. High performance liquid chromatograms (HPLC) were obtained fromC-8 or C-18 reverse phase columns which were obtained from severalvendors. Analytical samples were dried in an Abderhalden apparatus ateither 56° C. or 78° C. ¹H NMR spectra were obtained from either GeneralElectric QE-300 or Varian VXR 400 MHz spectrometer. ¹³C NMR spectra wereobtained from a Varian spectrometer at 125.8 MHz.

EXAMPLE 1 N⁶-[1-(Hydroxyimino)ethyl]-L-lysine, Dihydrochloride

EX-IA) To a 125 mL flask was added 3 g (0.012 mol) of α-Boc-L-lysine and70 mL of water. This solution was adjusted to pH=9.5 by addition of 2.5N NaOH. To this solution was added portion wise, 2.3 g ofchloroacetaldoxime which was prepared immediately prior to use by thereaction of 3.55 g (0.06 mol) of acetaldoxime with 10.4 g (0.78 mol) ofN-chlorosuccinimide in 65 mL of N,N-dimethylformamide at 0° C. Thechloroacetaldoxime was isolated after three hours by extracting intodiethyl ether and washing with aqueous NaCl. Drying with MgSo₄,filtration and concentration under 30° C. afforded thechloroacetaldoxime as a pale yellow oil. During the chloroacetaldoximeaddition, the pH was kept at 9.5 via concomitant addition of 2.5 N NaOH.After the addition was complete, the solution was allowed to stand at25° C. for 25 minutes. The solution was then adjusted to pH=7.5 with 1NHCl and poured onto a Dowex 50 Cation exchange column. The column waswashed with water. The Boc-protected product was then eluted with 10%aqueous pyridine.

EX-1) After concentrating, the product was deprotected by allowing it tostand in 2N HCl at 25° C. for two hours. Concentrating in vacuo afforded2.9 g (78%) of L-N⁶-(oximinoethyl)lysine dihydrochloride as a viscousyellow oil. ¹H-NMR(D₂O) 1.25-1.45 (m, 2H), 1.5-1.6 (m, 2H), 1.75-1.9 (m,2H), 2.05 (s, 3H), 3.25 (t, 2H), 3.95 (t, 1H); Mass Spectra, M+H=204.

EXAMPLE 2 2-Amino-5-[[1-(Hydroxyimino)ethyl]amino]-2-MethylpentanoicAcid, Dihydrochloride

α-Methyl-D,L-ornithine hydrochloride is protected as a copper complexvia reaction with cupric carbonate in water at reflux. This protectedamino acid is then reacted with chloroacetaldoxime as in Example 1. Theproduct is eluted from Dowex with 1N ammonium hydroxide. Concentrationin vacuo, followed by acidification with hydrochloric acid affords thetitle compound.

EXAMPLE 3 N6-[1-(Hydroxyimino)ethyl]-2-methyl-lysine, Dihydrochloride

EX-3A) A suspension of lysine ethyl ester dihydrochloride (33 g; 0.14mole) and MgSO₄ (34 g; 0.28 moles) in a solution of4-chloro-benzaldehyde (39 g; 0.28 moles) and acetonitrile (500 mL) wasstirred while N,N-diisopropylethylamine (36 g; 0.28 moles) was added inportions over ½ h. The mixture was stirred for 12 h, filtered,concentrated to a small volume, and diluted with 500 mL of diethylether. The ether solution was washed with 0.1% aqueous NaHCO₃, aqueous 2N NaOH containing 2 g/100 ml of NH₂OH.HCl, again with 0.1% aqueousNaHCO₃ and saturated aqueous NaCl. After drying with MgSO₄ and removalof the solvent in vacuo, ethylN,N′-di(4-chloro-phenylmethylene)-L-lysine was obtained as a clearliquid.

EX-3B) The liquid was triturated with hexanes and the resulting solidwas washed with hexanes. This partially purified intermediate wasdissolved in 200 mL of THF and stirred in an acetone/dry ice bath.Sodium bis-(trimethylsilyl)amide in THF (11 mL, 1 M solution) was addeddropwise over 30 min. After one hour, methyl iodide (0.8 g; 13 mmoles)in THF was added dropwise. The reaction mixture was slowly warmed up toroom temperature and stirred overnight. The mixture was diluted withwater, and extracted with ethyl ether. The ether extract was washed with0.1% aqueous NaHCO₃ and saturated aqueous NaCl and concentrated to yieldcrude ethyl N.N′-di(4-chloro-phenylmethylene)-α-methyl-D,L-lysine(M+H=434).

EX-3C) This material (4 g) was dissolved in ethyl ether (100 ml) wasstirred vigorously with 1 N HCl (50 mL) for 2 h, the layer was separatedand the aqueous phase was washed with ethyl ether. The aqueous solutionwas further acidified by the addition of concentrated HCl to 6 N and washeated to reflux for 16 h. The solution was cooled to room temperature,and rotary evaporated to dryness. The residue was dissolved in water andapplied to a Dowex 50×4 (hydrogen form). The column was washed withwater, and then 10% pyridine. α-Methyl-D,L-lysine, (M+H=161) was elutedfrom the column with 1 M NH₄OH.

EX-3D) The α-methyl-D,L-lysine is protected as a copper complex viareaction with cupric carbonate in refluxing water.

EX-3) This protected amino acid is then reacted with chloroacetaldoximeas described in Example 1. The product is eluted from Dowex with 1Nammonium hydroxide. Concentration in vacuo, followed by acidificationwith hydrochloric acid affords the title compound.

EXAMPLE 42-[[2-[[1-(Hydroxyimino)ethyl]amino]ethylseleno]methyl]-L-alanine,Dihydrochloride

EX-4A) D,L-Selenocystine (117 mg; 0.5 mmoles, purchased from Sigma) wassuspended in 15 mL of nitrogen (N₂) gas-purged water. Sodium borohydride(38 mg; 1 mole) was added. The reaction mixture became clear in a fewminutes. After 2 h at room temperature, 2-bromoethylamine HCl (1.2 g; 6mmoles) was added and the reaction mixture was stirred for 12 h. Thereaction was applied on to a Dowex 50×4 (hydrogen form) column. Thecolumn was washed with water and 10% pyridine and2-aminoethyl-selenocysteine was eluted with 1 M NH₄OH.

EX-4B) The 2-aminoethyl-selenocysteine is protected and subsequentlymethylated as described in Example 3 to afford theα-methyl-(2-aminoethyl)selenocysteine.

EX-4C) The α-methyl-(2-aminoethyl)selenocysteine is protected as acopper complex via reaction with cupric carbonate in refluxing water.

EX-4) This protected amino acid is then reacted with chloroacetaldoximeas described in Example 1. The product is eluted from Dowex with 1Nammonium hydroxide. Concentration in vacuo, followed by acidificationwith hydrochloric acid affords the title compound.

EXAMPLE 5 N⁶-[1-(Hydroxyimino)ethyl]-2-(hydroxymethyl)-lysine,Dihydrochloride

EX-5A) To an ice-cold stirred mixture of N^(ε)-Cbz-L-lysine (14 g; 0.05moles, purchased from Sigma) in 2.5 N NaOH (24 mL), benzoyl chloride (10g) was added gradually. The pH of the solution was maintained at10.5-10.9 by addition of 2 N NaOH. The mixture was stirred at roomtemperature for 1 h and filtered. The filtrate was extracted with asmall amount of ethyl acetate and the organic layer was dried oversodium sulfate. The solid was removed by filtration and the filtrate wasevaporated to dryness.

EX-5B) The crude oily N^(ε)-Cbz-N^(α)-benzoyl-lysine residue (6 g) washeated at 90-100° C. in acetic anhydride (100 mL) for 30 min. Themixture was then evaporated. The residue was dissolved in pyridine andtreated with aqueous formaldehyde (35% solution, Fisher). The mixturewas stirred for 8 hr and then diluted. The reaction mixture was kept at10° C. overnight. The precipitated crude material was hydrolyzed byboiling in 5 N HCl for 5 h. The reaction mixture was cooled and filteredbefore being evaporated. The solid residue was dissolved in water andpassed through Dowex 50×4 (hydrogen form) column.α-Hydroxymethyl-D,L-lysine (M+H=177) was eluted with 1 N NH₄OH.

EX-5C) The α-hydroxymethyl-D,L-lysine is protected as a copper complexvia reaction with cupric carbonate in water at reflux.

EX-5) This protected amino acid is then reacted with chloroacetaldoximeas described in Example 1. The product is eluted from Dowex with 1Nammonium hydroxide. Concentration in vacuo, followed by acidificationwith hydrochloric acid affords the title compound.

EXAMPLE 6 N⁶-[1-(Hydroxyimino)-2,2,2-trifluoroethyl]-L-lysine,Dihydrochloride

α-Boc-L-lysine is reacted with chlorotrifluoroacetaldoxime (J. Org.Chem. 49, (1984) 919-922) as described in Example 1 to afford the titlecompound.

EXAMPLE 7 N⁶-[1-(Hydroxyimino)ethyl]-L-lysine, Ethyl Ester,Dihydrochloride

EX-7A) To a 125 mL flask is added 0.012 mol of α-Boc-L-lysine ethylester hydrochloride and 70 mL of water. This solution is adjusted topH=8.5 by addition of 2.5 N NaOH. To this solution is added portionwise, 2.3 g of chloroacetaldoxime which is prepared immediately prior touse by the reaction of 3.55 g (0.06 mol) of acetaldoxime with 10.4 g(0.78 mol) of N-chlorosuccinimide in 65 mL of N,N-dimethylformamide at0° C. The chloroacetaldoxime is isolated after three hours by extractinginto diethyl ether and washing with aqueous NaCl. Drying with MgSO₄,filtering and concentrating under 30° C. affords the chloroacetaldoximeas a pale yellow oil. During the chloroacetaldoxime addition, the pH iskept at 8.5 via concomitant addition of 2.5 N NaOH. After the additionis complete, the solution is allowed to stand at 25° C. for 25 minutes.The solution is then adjusted to pH=7.5 with 1N HCl and poured onto aDowex 50 Cation exchange column. The column is washed with water. TheBoc-protected product is then eluted with 10% aqueous pyridine.

EX-7) After concentrating, the product is deprotected by allowing it tostand in 4N HCl in ethanol at 25° C. for twelve hours. Concentrating invacuo at 30° C. affords L-N⁶-(hydroximinoethyl)lysine ethyl esterdihydrochloride.

EXAMPLE 8 N⁶-[1-(Hydroxyimino)ethyl]-L-lysine, 2,3-DihydroxypropylEster, Dihydrochloride

EX-8A) ε-Z-α-Boc-L-Lysine is reacted with DL-isopropylideneglycerol(Aldrich Chemical Co., Milwaukee, Wis., USA) in DMF in the presence of1-hydroxybenzotriazole hydrate and[(N,N-dimethylamino)propyl]ethylcarbodiimide hydrochloride as describedin 23c to give 8a.

EX-8B) The benzyloxycarbonyl (Z) group of 8a is removed withhydrogenolysis using 5% Pd/C in ethanol and the resulting deprotectedamine is reacted with chloroacetaldoxime as described in the preparationof 7a to give 8b.

EX-8) 8b is treated with 6M HCl in anhydrous ethanol overnight,evaporated to a solid, and triturated with ether to give the titlecompound 8.

EXAMPLE 9 N⁶-[1-(Hydroxyimino)ethyl]-L-lysine,2-hydroxy-1-(hydroxymethyl)ethyl Ester, Dihydrochloride

EX-9A) The process of Example 8 is repeated, with1,3-benzylideneglycerol (H. Hibbert, N. M. Carter, J. Am. Chem. Soc.,1929, 51, 1601) replacing DL-isopropylideneglycerol.

EX-9B) After the chloroacetaldoxime step, the benzylidene group isremoved with triethyl borate/boric acid as described in J. Med. Chem.1980, ,23, 9-12 (G. Y. Paris et al). The reaction product is purified byreverse phase column chromatography.

EX-9) The title compound is procured after HCl/EtOH treatment asdescribed in Example 8.

EXAMPLE 10 N⁶-[1-(Hydroxyimino)ethyl]-L-lysine,2-(diethylamino)-2-oxoethyl Ester, Dihydrochloride

EX-10A) ε-Boc-α-Z-L-Lysine is reacted with 2-chloro-N,N-diethylacetamide(Aldrich Chemical Co.) in the presence of triethylamine and sodiumiodide by the method described in Internat. J. Pharmaceutics, 1990, 62,193-205 (A. H. Kahns and H. Bundgaard) to give 10a.

EX-10) 10a is treated sequentially with HCl 4M in glacial acetic acidfor three hours and then stripped to remove the Boc group, thenchloroacetaldoxime as described in Example 7, and then hydrogenolyzedwith 5% Pd/C in ethanol containing excess HCl and filtered and strippedto give the title compound.

EXAMPLE 11 S-Ethyl2S-Amino-6-[[1(hydroxyimino)ethyl]amino]hexanethioate, Dihydrochloride

EX-11a) To a flask containing N-α-Boc-N-ε-Z-L-lysine in a suitablesolvent is added an amino acid activating agent. This transientintermediate is then reacted with ethanethiol to produce the protectedthioester.

EX-11B) The product of EXAMPLE 11a dissolved in an appropriate solventis combined with a hydrogenation catalyst such as palladium on carbonand hydrogen. This reaction is shaken under pressure for an extendedperiod of time in a standard Parr hydrogenation apparatus to remove theZ-function generating the amino product illustrated below.

EX-11c) The product of EXAMPLE 11b dissolved in an appropriate solventis reacted with the chloroacetaldoxime whose synthesis is described inEXAMPLE 1 to yield the hydroxyimino material illustrated below.

EX-11) The product of EXAMPLE 11c dissolved in an appropriate solvent isreacted with HCl to remove the Boc-protecting group and provide thetitle compound.

EXAMPLE 12 N²-[(Acetyloxy)methyl]-N⁶-[1-(hydroxyimino)ethyl]-L-lysine,Dihydrochloride

EX-12A) To a flask containing N-α-Boc-N-ε-Z-L-lysine in a suitablesolvent is added an amino acid activating agent. This transientintermediate is then reacted with benzylalcohol to produce the protectedbenzylester product illustrated below.

EX-12B) The product of EXAMPLE 12a dissolved in an appropriate solventis reacted with HCl to remove the Boc-protecting group and provide theproduct illustrated below.

EX-12C) The product of EXAMPLE 12b dissolved in an appropriate solventis reacted with formaldehyde, Cs₂CO₃, and acetic anhydride to providethe product illustrated below.

EX-12D) The product of example 12c is dissolved in an appropriatesolvent and combined with a hydrogenation catalyst such as palladium oncarbon and hydrogen. This reaction is shaken under pressure for anextended period of time in a standard Parr hydrogenation apparatus toremove the Z-function generating the amino product illustrated below.

EX-12) The product of EXAMPLE 12d dissolved in an appropriate solvent isreacted with the chloroacetaldoxime whose synthesis is described inEXAMPLE 1 to yield the hydroxyimino title material.

EXAMPLE 13N⁶-[1-(Hydroxyimino)ethyl]-N²-[[[(methylamino)carbonyl]oxy]methyl]-L-lysine,Dihydrochloride

EXAMPLE 14N⁶-[1-(Hydroxyimino)ethyl]-N²-[[(methoxycarbonyl)oxy]methyl]-L-lysine,Dihydrochloride

EXAMPLE 15N⁶-[1-(Hydroxyimino)ethyl]-N²-[[[(methylthio)carbonyl]oxy]methyl]-L-lysine,Dihydrochloride

EXAMPLE 16N⁶-[1-(Hydroxyimino)ethyl]-N²-[[(phenylcarbonyl)oxy]methyl]-L-lysine,Dihydrochloride

EXAMPLE 17N²-Acetyl-N²-[(acetyloxy)methyl]-N⁶-[1-(hydroxyimino)ethyl]-L-lysine,Hydrochloride

EX-17A) The product of EXAMPLE 12b dissolved in an appropriate solventis reacted with Cs₂CO₃, and acetic anhydride to provide the productillustrated below.

EX-17B) The product of EXAMPLE 17a dissolved in an appropriate solventis combined with a hydrogenation catalyst such as palladium on carbonand hydrogen. This reaction is shaken under pressure for an extendedperiod of time in a standard Parr hydrogenation apparatus to remove theZ-function generating the amino product illustrated below.

EX-17) The product of EXAMPLE 17b dissolved in an appropriate solvent isreacted with the chloroacetaldoxime whose synthesis is described inEXAMPLE 1 to yield the hydroxyimino title material.

EXAMPLE 18N⁶-[1-(Hydroxyimino)ethyl]-N²-[(methylthio)carbonyl]-L-lysine,Hydrochloride

EXAMPLE 19N²-[(1,1-Dimethylethoxy)carbonyl)-N⁶-[1-(hydroxyimino)ethyl]-L-lysine,Hydrochloride

To a 125 mL flask was added 3 g (0.012 mol) of a-Boc-L-lysine and 70 mLof water. This solution was adjusted to pH=9.5 by addition of 2.5 NNaOH. To this solution was added portion wise, 2.3 g ofchloroacetaldoxime which was prepared immediately prior to use by thereaction of 3.55 g (0.06 mol) of acetaldoxime with 10.4 g (0.78 mol) ofN-chlorosuccinimide in 65 mL of N,N-dimethylformamide at 0° C. Thechloroacetaldoxime was isolated after three hours by extracting intodiethyl ether and washing with aqueous NaCl. Drying with MgSO₄,filtration and concentration under 30° C. afforded thechloroacetaldoxime as a pale yellow oil. During the chloroacetaldoximeaddition, the pH was kept at 9.5 via concomitant addition of 2.5 N NaOH.After the addition was complete, the solution was allowed to stand at25° C. for 25 minutes. The solution was then adjusted to pH=7.5 with 1NHCl and poured onto a Dowex 50 Cation exchange column. The column waswashed with water. The Boc-protected product was then eluted with 10%aqueous pyridine. ¹H-NMR(D₂O) 1.25 (s, 9H); 1.4-1.65 (m, 6H), 2.05 (s,3H), 3.22 (t, 2H), 3.75 (m, 1H); Mass Spectra, M+H=304.

EXAMPLE 20N⁶-[1-(Hydroxyimino)ethyl]-N²-[(methylamino)carbonyl]-L-lysine,Hydrochloride

EX-20A) Epsilon-Boc-lysine is allowed to react with methyl isocyanate toafford the urea.

EX-20B) Deprotection with HCl removes the Boc to afford the amine.

EX-20) Reaction with acetaldoximinoyl chloride as in example 1 affordsthe title product.

EXAMPLE 21N⁶-[1-(Hydroxyimino)ethyl]-N²-[N⁶-[1-(hydroxyimino)ethyl]-L-lysyl]-L-lysine,Ethyl Ester, Trihydrochloride

EX-21A) ε-Boc-L-Lys(Z)-OH (3.8 g, 10 mmol) in 25 mL DMF and 25 mLdichloromethane (DCM) is reacted with isobutyl chloroformate (1.4 mL,(10 mmol) in the presence of NMM (1.1 mL, 10 mmol). The resulting mixedanhydride is reacted with 10 mmol ε-Boc-L-Lys-OEt HCl salt suspended in25 mL DMF containing 10 mmol NMM. After mixing for 16 hr, the reactionmixture is filtered, the residue washed with DCM (25 mL), and thecombined filtrate and wash is extracted by 0.5 M KHSO₄ solution,followed by water extraction, and then brine extraction. The organicphase is dried (MgSO₄), filtered, and stripped to an oil. The oil ispurified by silica gel chromatography if necessary, giving 21a.

EX-21B) 21a is treated with 4 M HCl in ethanol overnight at roomtemperature. The reaction mixture is stripped to a solid, giving 21b.

EX-21C) 21b is dissolved in water, and the pH is adjusted to 8.5 with2.5 N NaOH. This solution is treated with a fivefold excess ofchloroacetaldoxime as described in example 7, through the elution withaqueous pyridine. The product is stripped to an oil, giving 21c.

EX-21) 21c is hydrogenolyzed (H₂ 10 psi) with 5% Pd/C in ethanolcontaining an excess of HCl. The title compound 21 is isolated bystripping the solution to a solid, and triturating this solid withether.

EXAMPLE 22N⁶-[1-(Hydroxyimino)ethyl]-N²-[N⁶-[1-(hydroxyimino)ethyl]-L-lysyl]-L-lysine,Trihydrochloride

The procedure of Example 21 is repeated, with the HCl salt ofε-Boc-L-Lys benzyl ester (ε-Boc-L-Lys-OBz HCl) replacing theε-Boc-L-Lys-OEt HCl salt. The final hydrogenolysis then gives the titlecompound.

EXAMPLE 23N⁶-[1-(Hydroxyimino)ethyl]-N²-[N⁶-(1-iminoethyl)-L-lysyl]-L-lysine,Ethyl Ester, Trihydrochloride

EX-23A) α-Z-L-Lysine ethyl ester in 10 mL DMF is treated with methylacetimidate (0.692 g, 6 mmol) and N,N-diisopropylethylamine (1.05 mL, 6mmol) overnight. Solvent is removed in vacuo and the residue is purifiedby reverse phase column chromatography, giving 23a.

EX-23B) The product N⁶-[1-iminoethyl]-L-Lys(Z)-OEt trifluoroacetate(TFA) salt (23a) is treated with refluxing aqueous 6M HCl overnight andstripped to give N⁶-[1-iminoethyl]-L-Lys(Z)-OH HCl salt (BP4b). Passagethrough an anion exchange column in the chloride form can be used ifnecessary to fully replace the TFA.

EX-23C) To a stirring solution of N⁶-[1-iminoethyl]-L-Lys(Z)-OH HCl salt(23b, 13.8 mmol), ε-Boc-L-Lys-OEt (39.5 mmol), and1-hydroxybenzotriazole hydrate (2 g, 14.5 mmol) in 75 mL ofdimethylformamide (DMF) cooled in an ice bath is added[(N,N-dimethylamino)propyl]ethylcarbodiimide hydrochloride (2.8 g, 14.5mmol). After stirring 55 h at ambient temperature, the reaction mixtureis concentrated in vacuum. The resulting material is dissolved inaqueous acetonitrile and passed through a reverse phase hromatographiccolumn, giving [α-(Z)-ε-N-iminoethyl-L-Lysyl-ε-Boc-L-Lysine ethyl esterTFA salt (23c).

EX-23) This material is treated with ethanolic HCl as described for 21b,dissolved in water and treated with chloroacetaldoxime, followed byhydrogenolysis, both as described in Example 21, to give the titlecompound 23.

EXAMPLE 24N⁶-[1-(Hydroxyimino)ethyl]-N²-(N⁶-(1-iminoethyl)-L-lysyl]-L-lysine,Trihydrochloride

The procedure of Example 23 is carried out, with ε-Boc-L-Lys-OBzreplacing ε-Boc-L-Lys-OEt, to give the title compound.

EXAMPLE 25N²-(N-Acetyl-L-methionyl)-N⁶-[1-(hydroxyimino)ethyl]-L-lysine, EthylEster, Hydrochloride

The procedure of Example 21 is run through the elution with aqueouspyridine, with N-acetyl-L-methionine replacing ε-Boc-L-Lys(Z)-OH. Theaqueous pyridine solution is stripped to a solid, dissolved in diluteHCl, and shelled and lyophilized to give title compound.

EXAMPLE 26 N²-(N-Acetylmethionyl)-N⁶-[1-(hydroxyimino)ethyl]-L-lysine,Hydrochloride

The title compound of Example 25 is treated with refluxing aqueous 6NHCl for 12 hr and then stripped to a solid to give the title compound.

EXAMPLE 27 N²-(L-Alanyl)-N⁶-[1-(Hydroxyimino)ethyl]-L-lysine,Dihydrochloride

EX-27A) The product of example 1 is dissolved in ethanol, cooled down inice bath and HCl gas is bubbled into the solution. This solution isstirred at room temperature followed by removal of the solvent in vacuoto obtain the ethyl ester.

EX-27B) This ester is coupled with N^(α)-Boc-L-alanine indimethylformamide (DMF) in the presence of[2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate](TBTU) and diisopropylethylamine (DIPEA). The solvent is removed invacuo and the product is isolated on preparative HPLC usingacetonitrile/H₂O gradient.

EX-27) Protecting groups are removed in 2N HCl at reflux. The titlecompound is isolated on preparative HPLC using acetonitrile/H₂Ogradient.

EXAMPLE 28 N⁶-[1-[[(Methoxycarbonyl)oxy]imino]ethyl]-L-lysine,Dihydrochloride

EXAMPLE 29 N⁶-[1-[[[(Methylamino)carbonyl]oxy]imino]ethyl]-L-lysine,Dihydrochloride

EXAMPLE 30 N⁶-1-[[[(Methylthio)carbonyl]oxy]imino]ethyl]-L-lysine,Dihydrochloride

EXAMPLE 31 N⁶-[1-[(Acetyloxy)imino]ethyl]-L-lysine, Dihydrochloride

EX-31A) To N-alpha-boc-L-lysine (Aldrich) in water at pH 9, is addedO-acetyl-2-chloroacetaldehyde oxime, adjusting to pH 9 throughout thereaction with 2.5N sodium hydroxide. Contents are purified on a Dowex-50cation exchange resin, eluting the boc-protected product with 1Nammonium hydroxide.

EX-31) Acidic hydrolysis and purification by C18 reverse phasechromatography affords the desired product.

EXAMPLE 32 N⁶-[1-[[(Phenylcarbonyl)oxy]imino]ethyl]-L-lysine,Dihydrochloride

EXAMPLE 33 N⁶-[1-[(Methoxyimino)ethyl]-L-lysine, Dihydrochloride

EX-33A) To N-alpha-boc-L-lysine (Aldrich) in water at pH 9, is addedO-methyl-2-chloroacetaldehyde oxime, adjusting to pH 9 throughout thereaction with 2.5N sodium hydroxide. Contents are purified on a Dowex-50cation exchange resin, eluting the boc-protected product with 1Nammonium hydroxide.

EX-33) Acidic hydrolysis and purification by C18 reverse phasechromatography affords the desired product.

EXAMPLE 34 N⁶-[1-[(Phenoxyimino)ethyl]-L-lysine, Dihydrochloride

EXAMPLE 35 N⁶-Hydroxy-N⁶-[1-(hydroxyimino)ethyl]-L-lysine,Dihydrochloride

EXAMPLE 36N⁶-[1-(Hydroxyimino)ethyl]-N⁶-[[(methoxycarbonyl)oxy]methyl]-L-lysine,Dihydrochloride

EXAMPLE 37N⁶-[1-(Hydroxyimino)ethyl]-N⁶-[[[(methylamino)carbonyl]oxy]methyl]-L-lysine,Dihydrochloride

EXAMPLE 38N⁶-[1-(Hydroxyimino)ethyl]-N⁶-[[[(methylthio)carbonyl]oxy]methyl]-L-lysine,Dihydrochloride

EXAMPLE 39N⁶-[1-(Hydroxyimino)ethyl]-N⁶-[[(phenylcarbonyl)oxy]methyl]-L-lysine,Dihydrochloride

EXAMPLE 40 N6-(Acetyloxy)-N6-(1-iminoethyl)-L-lysine, Dihydrochloride

EX-40A) α-Cbz-protected hydroxylysine methyl ester was prepared asdescribed in J. Org. Chem. 59, 4858-4861 (1994). This material was thenallowed to react with ethyl acetimidate to afford the hydroxamidine.Mass spectral analysis for C₁₇H₂₅N₃O₅:M+H=352.

EX-40B) Reaction with acetic anhydride affords the acetylhydroxamidine.

E-40) Deprotection with HBr in acetic acid affords the title compound.

EXAMPLE 41 N⁶-[1-[(Phenylthio)imino]ethyl]-L-lysine, Dihydrochloride

EXAMPLE 42 N⁶-(1-Iminoethyl)-N⁶-(phenylmethoxy)-L-lysine,Dihydrochloride

EX-42A) Omega benzyloxy acetyllysine methyl ester is prepared asdescribed in Tet. Let. 25(9), 927-930 (1994). This material ishydrolyzed to afford benzyloxylysine.

EX-42) Protection of the amino acid with Cu²⁺ allows reaction with ethylacetimidate in basic water. Purification via Dowex 50 ion exchange resinaffords the title compound.

EXAMPLE 43 N⁶-Hydroxy-N⁶-(1-iminoethyl)-L-lysine, Dihydrochloride

EXAMPLE 44 N6-Acetyloxy-N6-[1-[(acetyloxy)imino]ethyl]-L-lysine,Dihydrochloride

EX-44A) α-Cbz-protected hydroxylysine methyl ester is prepared asdescribed in J. Org. Chem. 59, 4858-4861 (1994). This material is thenallowed to react with acetaldoximinoyl chloride to afford the N,N′dihydroxyamidine.

EX-44B) Reaction with acetic anhydride affords the bis-acetoxyamidine.

EX-44) Deprotection with HBr in acetic acid affords the title compound.

EXAMPLE 45N⁶-[[1-[(Methoxycarbonyl)oxy]imino]ethyl]-N⁶-[(methoxycarbonyl)oxy]-L-lysine, Dihydrochloride

EXAMPLE 46N⁶-[1-[[[(Methylamino)carbonyl]oxy]imino]ethyl]-N⁶-[[(methylamino)carbonyl]oxy]-L-lysine,Dihydrochloride

EXAMPLE 47N6-[1-[[[(Methylthio)carbonyl]oxy]imino]ethyl]-N6-[[(methylthio)carbonyl]oxy]-L-lysine,Dihydroch1oride

EXAMPLE 48N⁶-[1-[[(Phenylcarbonyl)oxyimino]ethyl]-N⁶-[(phenylcarbonyl)oxy]-L-lysine,Dihydrochloride

EXAMPLE 49 N⁶-[1-(Phenoxyimino)ethyl]-N⁶-phenoxy-L-lysine,Dihydrochloride

EXAMPLE 50 N⁶-[1-(Methoxyimino)ethyl]-N⁶-(phenylmethoxy)-L-lysine,Dihydrochloride

EX-50A) Omega benzyloxy acetyllysine methyl ester is prepared asdescribed in Tet. Let. 25(9), 927-930 (1994). This material ishydrolyzed to afford benzyloxylysine.

EX-50) Protection of the amino acid with Cu²⁺ allows reaction withO-methyl acetoximinoyl chloride in basic water. Purification via Dowex50 ion exchange resin affords the title compound.

EXAMPLE 51 N⁶-[1-[[(Acetyloxy)methyl]imino]ethyl]-N⁶-hydroxy-L-lysine,Dihydrochloride

EX-51A) [α-Cbz-protected hydroxylysine methyl ester is prepared asdescribed in J. Org. Chem. 59, 4858-4861 (1994). This material is thenallowed to react with CH₃C(OEt)=NCH₂OAc to afford the hydroxamidine.

EX-51) Deprotection with HBr in acetic acid affords the title compound.

EXAMPLE 52N⁶-Hydroxy-N⁶-[1-[[[(methoxycarbonyl)oxy]methyl]imino]ethyl]-L-lysine,Dihydrochloride

EXAMPLE 53N⁶-Hydroxy-N⁶-[1-[[[(methylamino)carbonyl]oxy]methyl]imino]ethyl]-L-lysine,Dihydrochloride

EXAMPLE 54 N⁶-Hydroxy-N⁶-[1-[[[(methylthio)carbonyl]oxy]methyl]imino]ethyl]-L-lysine,Dihydrochloride

EXAMPLE 55N⁶-Hydroxy-N⁶-[1-[[[(phenylcarbonyl)oxy]methyl]imino]ethyl]-L-lysine,Dihydrochloride

EXAMPLE 56 N⁶-[(Acetyloxy)methyl]-N⁶-[1-(hydroxyimino)ethyl]-L-lysine,Dihydrochloride

EX-56A) α-Fmoc, ε-Cbz-lysine is allowed to react with formaldehydefollowed by acetic anhydride.

EX-56B) Deprotection of the Cbz via catalytic hydrogenation affords theacetoxymethyl lysine.

EX-56) Reaction of this material with acetaldoximinoyl chloride followedby Fmoc deprotection affords the title compound.

EXAMPLE 57 N⁶-(1-Iminoethyl)-N⁶-[(methoxycarbonyl)oxy]-L-lysine,Dihydrochloride

EXAMPLE 58 N⁶-(1-Iminoethyl)-N⁶-[[(methylamino)carbonyl]oxy]-L-lysine,Dihydrochloride

EXAMPLE 59 N⁶-(1-Iminoethyl)-N⁶-[[(methylthio)carbonyl]oxy]-L-lysine,Dihydrochloride

EXAMPLE 60 N⁶-(1-Iminoethyl)-N⁶-[(phenylcarbonyl)ox-y]-L-lysine,Dihydrochloride

EXAMPLE 61 N⁶-(1-Iminoethyl)-N⁶-phenoxy-L-lysine, Dihydrochloride

EXAMPLE 62 N⁶-(1-[(Methylthio)iminolethyl]-L-lysine, Dihydrochloride

EX-62A) To a flask is added N-α-Boc-L-lysine methyl ester hydrochlorideand water. This solution is adjusted to pH=8.5 by addition of 2.5 NNaOH. To this solution is added portion wise, methylacetimidatehydochloride. During the methylacetimidate hydochloride addition, the pHis kept at 8.5 to 10 via concomitant addition of 2.5 N NaOH. After theaddition is complete, the solution is allowed to stand at 25° C. for 25minutes. The solution is then adjusted to pH=7.5 with 1N HCl and pouredonto a Dowex 50 Cation exchange column. The column is washed with water.The Boc-protected product is then eluted with 10% aqueous pyridine.

EX-62B) To a flask is added the amidine free base in chloroform at −70°C. followed by the addition of methanesulfenylchloride. The solvent isconcentrated under vacuum and the resulting material is triturated withether. The resulting product is collected by filtration andrecrystallized from alcohol.

EX-62) The product is then deprotected by allowing it to stand in 2N HClin ethanol at 25° C. The product is isolated by reverse phase HPLCchromatography.

EXAMPLE 63 N6-(1-Iminoethyl)-N6-(methylthio)-L-lysine, Dihydrochloride

EX-63A) To a flask is added N-α-Boc-L-lysine methyl ester hydrochlorideand water. This solution is adjusted to pH=8.5 by addition of 2.5 NNaOH. To this solution is added portion wise, methylacetimidatehydrochloride. During the methylacetimidate hydrochloride addition, thepH is kept at 8.5 to 10 via concomitant addition of 2.5 N NaOH. Afterthe addition is complete, the solution is allowed to stand at 25° C. for25 minutes. The solution is then adjusted to pH=7.5 with 1N HCl andpoured onto a Dowex 50 Cation exchange column. The column is washed withwater. The Boc-protected product is then eluted with 10% aqueouspyridine.

EX-63B) To a flask is added the amidine free base in chloroform at −70°C. followed by the addition of methanesulfenylchloride. The solvent isconcentrated under vacuum and the resulting material is triturated withether. The resulting product is collected by filtration andrecrystallized from alcohol.

EX-63) The product is then deprotected by allowing it to stand in 2N HClin ethanol at 25° C. The product is isolated by reverse phase HPLCchromatography.

EXAMPLE 64 N⁶-[1-Iminoethyl)-N⁶-(phenylthio)-L-lysine, Dihydrochloride

EXAMPLE 65 N⁶-[1-[(Phenylthio)imino]ethyl)-L-lysine, Dihydrochloride

EXAMPLE 665-(4-[[1-(Hydroxyimino)ethyl]amino]butyl]imidazolidine-2,4-dione,Dihydrochloride

The title product of EXAMPLE 1 dissolved in water is reacted potassiumcyanate in the presence of HCl as described in Bull. Soc. Chim. Fr.1954, 812, 815 to provide the title material

EXAMPLE 67 N-[N⁶-[1-(Hydroxyimino)ethyl]-L-lysyl]-L-alanine,Dihydrochloride

EXAMPLE 68 2S-Amino-6-[[1-(hydroxyimino)ethyl]amino]-4-hexenoic Acid,Dihydrochloride

EXAMPLE 69 N-(2S-Amino-2-(3-[[[1-(hydroxyimino)ethylamino]methyl]cyclopentyl]acetyl]-L-alanine, Dihydrochloride

EXAMPLE 70N-[2S-Amino-2-[3-[[[1-(hydroxyimino)ethyl]amino]methyl]isoxazol-5-yl]acetyl]-L-alanine,Dihydrochloride

EXAMPLE 71 N²-(4-Amino-1-oxobutyl)-N⁶-[1-(hydroxyimino)ethyl]-L-lysine,Ethyl Ester, Dihydrochloride

EX-71A) To a stirring solution of N-Boc-γ-aminobutyric acid (SigmaChemical Co., St. Louis, Mo., USA), ε-Z-L-Lys-OEt, and1-hydroxybenzotriazole hydrate in (DMF) cooled in an ice bath is added[(N,N-dimethylamino)propyl]ethylcarbodiimide hydrochloride as describedin Example 23c. After stirring 55 h at ambient temperature, the reactionmixture is concentrated in vacuum to a semisolid, and partitionedbetween ethyl acetate and water. The organic phase is washed with waterand then brine, dried (MgSO₄), filtered and stripped to give 71a.

EX-71) 71a is treated sequentially with 5% Pd/C in ethanol and hydrogenat 10 psi, then chloroacetaldoxime as described in Example 7, and thenHCl 4M in ethanol for thirteen hours and then stripped and trituratedwith ether to give the title compound.

EXAMPLE 72N²-[[(2-Aminoethyl)amino]carbonyl]-N⁶-[1-(hydroxyimino)ethyl]-L-lysine,Ethyl Ester, Dihydrochloride

EX-72A) ε-Z-L-Lys-OEt is treated with stochiometric amounts ofcarbonyldiimidazole and imidazole, both from Aldrich Chemical Co., inTHF, to give 72a.

EX-72B) After 12 hours at room temperature the product 72a is treatedwith an excess of t-butyl N-(2-aminoethyl)carbamate (N-Boc ethylenediamine, from Aldrich Chemical Co.) to give 72b.

EX-72) 72b is treated sequentially with 5% Pd/C in ethanol and hydrogenat 10 psi, then chloroacetaldoxime as described in Example 7, and thenHCl 4M in ethanol for thirteen hours and then stripped and trituratedwith ether to give the title compound

EXAMPLE 73N²-[(2-Aminoethoxy)carbonyl]-N⁶-[1-(hydroxyimino)ethyl]-L-lysine, EthylEster, Dihydrochloride

The process described in Example 72 is repeated, except thatN-Boc-glycinol (Aldrich Chemical Co.) replaces t-butylN-(2-aminoethyl)carbamate.

EXAMPLE 749S-Amino-5,6,7,8,9,10-hexahydro-3-methyl-4H-1,2,4-oxadiazecin-10-one,Dihydrochloride

The product of example 7 is heated in a high boiling solvent to effectethanol evolution. Removal of the solvent in vacuo followed bychromatographic purification affords the title compound.

EXAMPLE 75 3S-Aminohexahydro-1-[1-(hydroxyimino)ethyl]-2H-azepin-2-one,Dihydrochloride

EX-75A) 3-aminocaprolactam is protected with Boc anhydride to give thebis-protected aminocaprolactam after chromatographic isolation.

EX-75B) Formation of the amide anion with a lithium amide base followedby reaction with acetaldoximinoyl chloride affords the hydroxamidine.

EX-75) Deprotection with HCl affords the title product.

EXAMPLE 76

EX-76A) The product of example 1A is dissolved in methylene chloride. Tothis solution is added an equivalent each of DCC and Boc-aminotetrazole.Filtration retains the Boc-protected product in solution.

EX-76) Deprotection of example 76A with anhydrous HCl and purificationaffords the title compound.

EXAMPLE 77N-[4-Amino-5-(1H-imidazol-2-yl)-5-oxopentyl]-N′-hydroxyethanimidamide

EX-77A) A solution of 1-nitro,4-aminobutane is treated withchloroacetoxime as described in example 1A.

EX-77B) The product of example 77 A is treated with base followed byaddition of one equivalent of 2-(methoxycarbonyl)imidazole.

EX-77) Reduction of the product of example 77B affords the titlecompound.

EXAMPLE 78 N6-Hydroxy-N6-(2-hydroxy-1-iminoethyl)-L-lysine

EX-78A) The product of example 40 A is treated with methoxyacetimidateunder basic conditions to afford the hydroxamidine.

EX-78) Treatment of the product from example 78A with hydrobromic acidaffords the title compound.

EXAMPLE 79 4-[α-(N-(1-Iminoethyl)-aminomethyl)-α,α-dimethylsilyl]-2S-Aminobutanoic Acid, Dihydrochloride

EX-79A) A suspension of allylchloromethyldimethylsilane (5.7 g, 38 mmol;Aldrich), potassium phthalimide (7.81 g, 42 mmol; Aldrich) andtetrabutylammoniumiodide (154 mg) in DMF (50 mL) was heated at 70° C.for 4 hours under a N₂ atmosphere. The reaction mixture was then pouredonto ethyl acetate (EA) (100 mL) and extracted with brine (4×100 mL),the EA solution was then dried (Na₂SO₄) and evaporated under reducedpressure to yield EX-79A 9.36 g (94%) as an oil. ¹H NMR (CDCl₃, 300 MHZ)0.0 (s, 6H), 1.50-1.58 (m, 2H), 3.10 (s, 2H), 4.68-4.84 (m, 2H),5.59-5.68 (m, 1H), 7.54-7.61 (m, 2H), 7.64-7.72 (m, 2H).

EX-79B) A solution of EX-79A in CH₂Cl₂ at −78° C. is treated with ozone(20 min.) until a blue solution persists. The excess ozone is removed bypurging with O₂ until a clear solution results. Dimethylsulfide is thenadded to the solution which is then heated at 38° C. for 16 h. Thesolvent is removed under reduced pressure to yield the aldehyde EX-79B.

EX-79C) A solution Z-phosphonoglycine trimethyl ester in CH₂Cl₂ isreacted with DBU (1 equiv.). After the solution is stirred for 30minutes it is cooled to 0° C. followed by the addition of a solution ofthe aldehyde EX-79B (1 equiv.). The solution is then allowed to warm toRT and stir for 16 h. Additional CH₂Cl₂ is added and the solution isextracted with 1N HCl followed by brine, dried (Na₂SO₄) and evaporatedunder reduced pressure. The residue is chromatographed to yield EX-79C.

EX-79D) A solution of EX-79C in methanol is hydrogenated in the presenceof catalytic R,R-Rh-DIPAMP. The product is then chromatographed to yieldEX-79D.

EX-79E) A solution of EX-79D in alcohol is reacted with hydrazinemonohydrate (1 equiv.). The reaction solution is filtered and thesolvent removed under reduced pressure. The residue is purified byreverse phase HPLC to yield EX-79E.

EX-79F) The amine EX-79E is reacted with methyl acetimidate by themethod described for EX-63A. The product is purified by reverse phaseHPLC to yield EX-79F.

EX-79) A solution of EX-79F in 2N HCl is refluxed for 2 h. The solventis removed under reduced pressure and the residue is purified by reversephase HPLC to yield EX-79.

Biological Data

The subject compounds of formula (I) have been or are expected to befound to inhibit nitric oxide synthase and posses useful pharmacologicalproperties as demonstrated in one or more of the following assays:

Citrulline Assay for Nitric Oxide Synthase

NOS activity was measured by monitoring the conversion ofL-[2,3-³H]-arginine to L-[2,3- H]-citrulline. Mouse inducible NOS(miNOS) was prepared from an extract of LPS-treated mouse RAW 264.7cells and rat brain constitutive NOS (rnNOS) was prepared from anextract of rat cerebellum. Both preparations were partially purified byDEAE-Sepharose chromatography. Enzyme (10 μL) was added to 40 μL of 50mM Tris (pH 7.6) and the reaction initiated by the addition of 50 μL ofa solution containing 50 mM Tris (pH 7.6), 2.0 mg/mL bovine serumalbumin, 2.0 mM DTT, 4.0 mM CaCl₂, 20 μM FAD, 100 &Mtetrahydrobiopterin, 2.0 mM NADPH and 60 μM L-arginine containing 0.9μCi of L-[2,3-³H]-arginine. For constitutive NOS, calmodulin wasincluded at a final concentration of 40 nM. Following incubation at 37°C. for 15 minutes, the reaction was terminated by addition of 300 μLcold buffer containing 10 mM EGTA, 100 mM HEPES (pH 5.5) and 1.0 mML-citrulline. The [³H]-citrulline was separated by chromatography onDowex 50W X-8 cation exchange resin and radioactivity quantified with aliquid scintillation counter.

Raw Cell Nitrite Assay

RAW 264.7 cells are plated to confluency on a 96-well tissue cultureplate grown overnight (17 h) in the presence of LPS to induce NOS. A rowof 3-6 wells were left untreated and served as controls for subtractionof nonspecific background. The media was removed from each well and thecells are washed twice with Kreb-Ringers-Hepes (25 mM, pH 7.4) with 2mg/ml glucose. The cells are then placed on ice and incubated with 50 mLof buffer containing L-arginine (30 mM) +/− inhibitors for 1 h. Theassay is initiated by warming the plate to 37° C. in a water bath for 1h. Production of nitrite by intracellular iNOS is linear with time. Toterminate the cellular assay, the plate of cells is placed on ice andthe nitrite-containing buffer removed and analyzed for nitrite using apreviously published fluorescent determination for nitrite. T. P. Miskoet al, Analytical Biochemistry, 214, 11-16 (1993). All values are theaverage of triplicate wells and are compared to a background-subtractedinduced set of cells (100% value).

In Vivo Assay

Rats were treated with an intraperitoneal injection of 10 mg/kg ofendotoxin (LPS) with or without oral administration of the nitric oxidesynthase inhibitors. Plasma nitrites were measured 5 hourspost-treatment. The results show that the administration of the nitricoxide synthase inhibitor decreases the rise in plasma nitrites, areliable indicator of the production of nitric oxide, induced beendotoxin.

TABLE I Rodent (Cell Data and in vitro Enzyme Data) miNOS* Raw Cell*Compound IC50 [μM] rnNOS* IC50 [μM] Example 1 77 1470 28 *miNOS refersto mouse inducible NOS *rnNOS refers to rat brain constitutive NOS *RawCell refers to cultured RAW 264.7 cells

TABLE II Human (in vitro Enzyme Data) hiNOS* Compound IC50 [μM] hecNOS*hncNOS* Example 1 154 1474 907 *hiNOS refers to recombinant humaninducible NOS *hecNOS refers to recombinant human endothelialconstitutive NOS *hncNOS refers to recombinant human neuronalconstitutive NOS

TABLE III Low Dose LPS* in vivo Effective Dose (p.o., mg/kg/day)Compound 0.1 1 10 Example 1 0% inh. 54% inh. 97% inh. *Low Dose LPSrefers to the in vivo low-endotoxin assay carried out on rats asdescribed above.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention, and withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usage's andconditions.

What is claimed is:
 1. A compound having the formula;

and pharmaceutically acceptable salts, wherein: A is a heterocyclicring; R¹ is selected from the group consisting of H, hydroxyalkyl,alkoxyalkyl, alkyl and haloalkyl; R² is selected from the groupconsisting of straight and branched alkyl, alkenyl, and alkynyl,cycloalkyl, cycloalkenyl, haloalkyl; all optionally substituted by oneor more of alkyl, alkoxy, hydroxy, halogen, trifluoromethyl, nitro,cyano, or amino groups; R³ is selected from the group consisting of H,alkyl, alkenyl, CH₂OC(═O)YR⁶, alkylhydroxy, alkylpolyhydroxy, amino,hydroxy, alkyl(poly)oxyacyl, alkylcarboxy, optionally substituted by oneor more of alkyl, hydroxy, amino, carboxy, carboxyalkyl, alkylcarbonyl;R⁴ is selected from the group consisting of OH, SH, OR⁶, SR⁶, OC(═O)R⁶,SC(═O)R⁶, CH₂OC(═O)YR⁶, OC(═O)YR⁶, SC(═O)YR⁶, OSO₂R⁶, OS(O)R⁶; Y isindependently selected from the group consisting of O, S, CH₂, CHR⁶,C(R⁶)₂, NH, NR⁶; R⁵ is selected from H, OH, SH, OR⁶, SR⁶, OC(═O)R⁶,SC(═O)R⁶, CH₂OC(═O)YR⁶, OC(═O)YR⁶, SC(═O)YR⁶, OSO₂R⁶, OS(O)R⁶; R⁶ isselected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl,cycloalkyl, heterocyclic, aryl, heteroaryl all optionally substituted byone or more alkyl, alkoxy, hydroxy, halogen, trifluoromethyl, nitro,cyano, or amino groups; R⁷ is selected from the group consisting of H,S(O)R⁹, SO₂R⁹, CH₂OC(O)—R⁹, C(O)—R⁹ where C(O)—R⁹ is represented bynatural and synthetic amino acids or R⁹ is defined as below; R⁸ isselected from the group consisting of H, acyl; provided that R⁴, R⁵, R⁷and R⁸ are not simultaneously hydrogen, except when Q is SiE₂; R⁹ isselected from the group consisting of substituted dihydropyridyl, alkyl,thioalkoxy, alkoxy, amino, cycloalkoxy, optionally substituted with oneor more of amino, alkyl, alkylaryl, heteroaryl, alkylheteroaryl,alkylmercaptoalkyl, which may optionally be substituted with one or moreof hydroxy, amino, guanidino, iminoalkyl; X is selected from the groupconsisting of alkylene, alkenylene and alkynylene and which mayoptionally be substituted by one or more alkyl, alkoxy, hydroxy,halogen, trifluoromethyl, nitro, cyano, or amino groups; or X isselected from the group consisting of the formula —(CH₂)_(k)Q(CH₂)_(t)—where k is 1, 2 or 3, t is 1, 2 or 3 and Q is O (oxygen), Se, SiE₂ whereE is alkyl, aryl, and NR where R is H or alkyl which may be optionallysubstituted with alkyl, alkoxy, hydroxy, halogen, trifluoromethyl,nitro, cyano, amino; or X is selected from the group consisting of theformula —(CH₂)_(m)T(CH₂)_(n)— where m is 0, 1 or 2, n is 0, 1 or 2, T isa 3 to 6 membered carbocyclic or heterocyclic ring, aromatic ring orheteroaromatic ring which may optionally be substituted by one or moresubstituents selected from the group consisting of alkyl, alkoxy,hydroxy, halogen, nitro, cyano, trifluoroalkyl and amino.
 2. A compoundhaving the formula;

and pharmaceutically acceptable salts, wherein: A is a heterocyclicring; R¹ is selected from the group consisting of H, hydroxyalkyl offrom 1 to 4 carbon atoms, alkoxyalkyl of from 1 to 4 carbon atoms ineach position, alkyl of from 1 to 8 carbon atoms and haloalkyl of from 1to 4 carbon atoms; R² is selected from the group consisting of straightand branched alkyl of from 1 to 4 carbon atoms, alkenyl and alkynyl offrom 2 to 4 carbon atoms, cycloalkyl of from 1 to 4 carbon atoms,cycloalkenyl of from 3 to 8 carbon atoms, and haloalkyl of from 1 to 4carbon atoms; all optionally substituted by one or more of alkyl,alkoxy, hydroxy, halogen, trifluoromethyl, nitro, cyano, or aminogroups; R³ is selected from the group consisting of H, alkyl of from 1to 4 carbon atoms, alkenyl of from 2 to 4 carbon atoms, CH₂OC(═O)YR⁶,alkylhydroxy, alkylpolyhydroxy, alkyl(poly)oxyacyl, alkylcarboxy, amino,hydroxy, optionally substituted by one or more of alkyl of from 1 to 4carbon atoms, hydroxy, amino, carboxy, carboxyalkyl, alkylcarbonyl; R⁴is selected from the group consisting of H, OH, SH, OR⁶, SR⁶, OC(═O)R⁶,SC(═O)R⁶, CH₂OC(═O)YR⁶, OC(═O)YR⁶, SC(═O)YR⁶; Y is independentlyselected from O, S, CH₂, CHR⁶, C(R⁶)₂, NH, NR⁶; R⁵ is selected from thegroup consisting of H, OH, SH, OR⁶, SR⁶, OC(═O)R⁶, SC(═O)R⁶,CH₂OC(═O)YR⁶, OC(═O)YR⁶, SC(═O)YR⁶; R⁶ is selected from the groupconsisting of H, alkyl of from 1 to 4 carbon atoms, alkenyl and alkynylof from 2 to 4 carbon atoms, cycloalkyl of from 3 to 8 carbon atoms,heterocyclic of from 5 to 8 members, aryl, heteroaryl all optionallysubstituted by one or more alkyl of from 1 to 4 carbon atoms, alkoxy,hydroxy, halogen, trifluoromethyl, nitro, cyano, or amino groups; R⁷ isselected from the group consisting of H, S(O)R⁹, SO₂R⁹, CH₂OC(O)—R⁹,C(O)—R⁹ where C(O)—R⁹ is represented by natural and synthetic aminoacids or R⁹ is defined as below; R⁸ is selected from the groupconsisting of H and acyl; provided that R⁴, R⁵, R⁷ and R⁸ are notsimultaneously hydrogen, except when Q is SiE₂; R⁹ is selected from thegroup consisting of substituted dihydropyridyl, alkyl of from 1 to 4carbon atoms, thioalkoxy, alkoxy, amino, cycloalkoxy, optionallysubstituted with one or more of amino, alkyl of from 2 to 4 carbonatoms, alkylaryl, heteroaryl, alkylheteroaryl, alkylmercaptoalkyl, whichmay optionally be substituted with one or more of hydroxy, amino,guanidino, iminoalkyl; X is selected from the group consisting ofalkylene, alkenylene and alkynylene having 2 to 6 carbon atoms and whichmay optionally be substituted by one or more alkyl groups; or X isselected from the group consisting of the formula —(CH₂)_(k)Q(CH₂)_(t)—where k is 1, 2 or 3, t is 1, 2 or 3 and Q is O (oxygen), Se, SiE₂ whereE is alkyl, aryl and NR where R is H or alkyl which may be optionallysubstituted with alkyl, alkoxy, hydroxy, halogen, trifluoromethyl,nitro, cyano, amino; or X is selected from the group consisting of theformula —(CH₂)_(m)T(CH₂)_(n)— where m is 0, 1 or 2, n is 0, 1 or 2, T isa 3 to 6 membered carbocyclic or heterocyclic ring, aromatic ring orheteroaromatic ring which may optionally be substituted by one or moresubstituents selected from the group consisting of alkyl, alkoxy,hydroxy, halogen, nitro, cyano, trifluoroalkyl and amino.
 3. Thecompound as recited in claim 2 and pharmaceutically acceptable salts,wherein: A is a heterocyclic ring; R¹ is selected from the groupconsisting of H, hydroxyalkyl of from 1 to 4 carbon atoms, alkoxyalkylof from 1 to 4 carbon atoms in each position, alkyl of from 1 to 8carbon atoms and haloalkyl of from 1 to 4 carbon atoms; R² is selectedfrom the group consisting of straight and branched alkyl of from 1 to 4carbon atoms, alkenyl and alkynyl of from 2 to 4 carbon atoms,cycloalkyl of from 1 to 4 carbon atoms, cycloalkenyl of from 3 to 8carbon atoms, and haloalkyl of from 1 to 4 carbon atoms; all optionallysubstituted by one or more of alkyl, alkoxy, hydroxy, halogen, nitro,cyano, or amino groups; R³ is selected from the group consisting ofaryl, heteroaryl, alkylaryl, alkylheteroaryl, all optionally substitutedby one or more of halogen, nitrile, carboxy, carboxyalkyl,carboxyalkylaryl; or R³ is selected from the group consisting of H,alkyl of from 1 to 4 carbon atoms, alkenyl of from 2 to 4 carbon atoms,CH₂OC(═O)YR⁶, alkylhydroxy, amino, hydroxy, alkylpolyhydroxy,alkyl(poly)oxyacyl, alkylcarboxy; R⁴ is selected from the groupconsisting of H, OH, SH, OR⁶, SR⁶, OC(═O)R⁶, SC(═O)R⁶, CH₂OC(═O)YR⁶; Yis independently selected from the group consisting of O, S, CH₂, CHR⁶,C(R⁶)₂, NH, NR⁶; R⁵ is selected from the group consisting of H, OH, SH,OR⁶, SR⁶, OC(═O)R⁶, SC(═O)R⁶, CH₂OC(═O)YR⁶; R⁶ is selected from thegroup consisting of H, alkyl of from 1 to 4 carbon atoms, alkenyl andalkynyl of from 2 to 4 carbon atoms, cycloalkyl of from 3 to 8 carbonatoms, heterocyclic of from 5 to 8 members, aryl, heteroaryl alloptionally substituted by one or more alkyl of from 1 to 4 carbon atomsor hydroxy groups; R⁷ is selected from the group consisting of H,S(O)R⁹, SO₂R⁹, CH₂OC(O)—R⁹, C(O)—R⁹ where C(O)—R⁹ is represented bynatural and synthetic amino acids or R⁹ is defined as below; R⁸ isselected from the group consisting of H and acyl; provided that R⁴, R⁵,R⁷ and R⁸ are not simultaneously hydrogen, except when Q is SiE₂; R⁹ isselected from the group consisting of substituted dihydropyridyl, alkylof from 1 to 4 carbon atoms, thioalkoxy, alkoxy, amino, cycloalkoxy; Xis selected from the group consisting of alkylene, alkenylene andalkynylene having 2 to 6 carbon atoms and which may optionally besubstituted by one or more alkyl groups; or X is selected from the groupconsisting of the formula —(CH₂)_(k)Q(CH₂)_(t)— where k is 2 or 3, t is1 or 2 and Q is O (oxygen), Se, SiE₂ where E is alkyl, aryl and NR whereR is H or alkyl which may be optionally substituted with alkyl; or X isselected from the group consisting of the formula —(CH₂)_(m)T(CH₂)_(n)—where m is 0, 1 or 2, n is 0, 1 or 2, T is a 3 to 6 membered carbocyclicor heterocyclic ring, aromatic ring or heteroaromatic ring which mayoptionally be substituted by one or more substituents selected from thegroup consisting of alkyl, alkoxy, hydroxy, halogen, nitro, cyano,trifluoroalkyl and amino.
 4. The compound as recited in claim 3 whereinA is a heterocyclic ring containing from 1 to 4 nitrogen atoms; R¹ isselected from the group consisting of H, hydroxyalkyl of from 1 to 4carbon atoms and alkyl of from 1 to 8 carbon atoms; R² is selected fromthe group consisting of straight and branched alkyl of from 1 to 4carbon atoms and haloalkyl of from 1 to 4 carbon atoms; all optionallysubstituted by one or more of alkyl, alkoxy, hydroxy, halogen, or aminogroups; R³ is selected from the group consisting of aryl, heteroaryl,alkylaryl, alkylheteroaryl, all optionally substituted by one or more ofhalogen, nitrile, carboxy, carboxyalkyl, carboxyalkylaryl; or R³ is alsoselected from the group consisting of H, alkyl of from 1 to 4 carbonatoms and alkenyl of from 2 to 4 carbon atoms, amino, hydroxy; R⁴ isselected from H, OH, SH, OR⁶, SR⁶; R⁵ is selected from H, OH, SH, OR⁶,SR⁶; R⁶ is selected from hydrogen, alkyl of from 1 to 4 carbon atoms,alkenyl and alkynyl of from 2 to 4 carbon atoms and cycloalkyl of from 3to 8 carbon atoms; R⁷ is selected from H and C(O)—R⁹, where C(O)—R⁹ isrepresented by natural and synthetic amino acids; R⁸ is selected from Hand acyl; provided that R⁴, R⁵, R⁷ and R⁸ are not simultaneouslyhydrogen, except when Q is SiE₂; X is selected from the group consistingof alkylene, alkenylene and alkynylene having 2 to 6 carbon atoms andwhich may optionally be substituted by one or more alkyl groups; or X isselected from the group consisting of the formula —(CH₂)_(k)Q(CH₂)_(t)—where k is 2 or 3, t is 1 or 2 and Q is O (oxygen) and NR where R is Hor alkyl or X is selected from the group consisting of the formula—(CH₂)_(m)T(CH₂)_(n)— where m is 0, 1 or 2, n is 0, 1 or 2, T is a 3 to6 membered carbocyclic or heterocyclic ring, aromatic ring orheteroaromatic ring.
 5. The compound as recited in claim 4 wherein A isa heterocyclic ring containing from 1 to 4 nitrogen atoms; R¹ isselected from the group consisting of H, hydroxyalkyl of from 1 to 4carbon atoms and alkyl of from 1 to 8 carbon atoms; R² is selected fromthe group consisting of straight and branched alkyl of from 1 to 4carbon atoms and haloalkyl of from 1 to 4 carbon atoms; all optionallysubstituted by one or more of alkyl, alkoxy, hydroxy, halogen, or aminogroups; R³ is selected from the group consisting of heteroaryl,alkylaryl, alkylheteroaryl, all optionally substituted by one or more ofhalogen, carboxy, carboxyalkyl; or R³ is also selected from the groupconsisting of H or alkyl of from 1 to 4 carbon atoms, amino; R⁴ isselected from H, OH, SH, OR⁶, SR⁶; R⁵ is selected from H, OH, SH, OR⁶,SR⁶; R⁶ is selected from hydrogen, alkyl of from 1 to 4 carbon atoms andcycloalkyl of from 3 to 8 carbon atoms; R⁷ is selected from H andC(O)—R⁹, where C(O)—R⁹ is represented by natural and synthetic aminoacids; R⁸ is H; provided that R⁴, R⁵, R⁷ and R⁸ are not simultaneouslyhydrogen, except when Q is SiE₂; X is selected from the group consistingof alkylene, alkenylene and alkynylene having 2 to 6 carbon atoms andwhich may optionally be substituted by one or more alkyl groups; or X isselected from the group consisting of the formula —(CH₂)_(k)Q(CH₂)_(t)—where k is 2 or 3, t is 1 or 2 and Q is O (oxygen).
 6. A pharmaceuticalcomposition selected from the group consisting of;(S)-1-[2-amino-6-[[1-(hydroxyamino)ethylidene]amino]-1-oxohexyl]-1H-tetrazol-5-amine;andN-[4-amino-5-(1H-imidazol-2-yl)-5-oxopentyl]-N′-hydroxyethanimidamide.7. A method of inhibiting nitric oxide synthesis in a subject in need ofsuch inhibition by administering a therapeutically effective amount of acompound of claim
 1. 8. A method of selectively inhibiting nitric oxidesynthesis produced by inducible NO synthase over nitric oxide producedby the constitutive forms of NO synthase in a subject in need of suchselective inhibition by administering a therapeutically effective amountof a compound of claim
 1. 9. A method of lowering nitric oxide levels ina subject in need of such by administering a therapeutically effectiveamount of a compound of claim
 1. 10. A pharmaceutical compositioncomprising a compound of claim 1, together with one or morepharmaceutically acceptable carriers.